Resistance, resilience, and patchiness of invertebrate assemblages in native tussock and pasture streams in New Zealand after a hydrological disturbance

2003 ◽  
Vol 60 (6) ◽  
pp. 731-739 ◽  
Author(s):  
Adriano S Melo ◽  
Dev K Niyogi ◽  
Christoph D Matthaei ◽  
Colin R Townsend
Keyword(s):  
Species Richness ◽  
New Zealand ◽  
Spatial Scales ◽  
Patch Dynamics ◽  
Natural Disturbance ◽  
Species Density ◽  
Land Uses ◽  
Invertebrate Abundance ◽  
Invertebrate Assemblages

We generated hydrological disturbances to investigate the role of disturbance in New Zealand streams in two land uses: native tussock grasslands and exotic pasture catchments. We tested whether physical differences in streambed structure confer higher resistance and resilience in tussock sites than in pasture sites. We also investigated changes in patchiness (at spatial scales larger than 0.06 m2) caused by the disturbance. Invertebrate abundance decreased immediately after the disturbance. Species density remained unchanged, but species richness (rarefied) increased. Eight days after the disturbance event, abundance and species richness (rarefied) were similar to those of samples collected immediately before the disturbance. Resistance (measured as decrease in abundance) and resilience (measured as recovery within 8 days) did not differ significantly between the land uses. Patchiness increased in both stream types immediately after the disturbance but decreased to predisturbance levels after 8 days. Disturbance caused a redistribution of individuals among patches, some receiving individuals, others losing individuals, and some remaining unchanged. Our results conform with predictions of the patch dynamics concept and are consistent with results of studies of natural disturbance caused by floods.

scholarly journals A year in a Cerrado wet grassland: a non-seasonal island in a seasonal savanna environment

2008 ◽  
Vol 68 (3) ◽  
pp. 495-501 ◽  
Author(s):  
MV. Cianciaruso ◽  
MA. Batalha
Keyword(s):  
Species Richness ◽  
Plant Density ◽  
Spatial Scales ◽  
Regional Scale ◽  
Basal Area ◽  
Species Density ◽  
Cerrado Vegetation ◽  
Wet Grassland ◽  
Wet Grasslands ◽  
Cylindrical Volume

In some Cerrado regions where the water table is superficial and soils are hydromorphic, we may find wet grasslands. We studied temporal changes in some community descriptors, such as species density, plant density, basal area, and cylindrical volume in a Cerrado wet grassland in four different seasons of the year. We also compared the species richness and composition of the wet grassland with a hyperseasonal cerrado, and a seasonal cerrado. We found significant differences among the seasons only for species density. Chao-Sørensen similarity values varied from 0.86 to 0.99 and, in the wet grassland, were not different among the seasons. On the contrary, similarity values between the wet grassland and hyperseasonal and seasonal cerrados were low. Species richness was lower in the wet grassland and higher in the seasonal cerrado. As long as savannas are highly dynamic on all temporal and spatial scales, the wet grassland stability, at least in a short-term view, introduces an important heterogeneity in regional scale. Wet grasslands are also important in the Cerrado domain to increase b-diversity, since they are floristically dissimilar with cerrado vegetation.

Savanna fires govern community structure of ungulates in Bénoué National Park, Cameroon

2008 ◽  
Vol 24 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Erik Klop ◽  
Janneke van Goethem
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Body Mass ◽  
National Park ◽  
Virtual Communities ◽  
Spatial Scales ◽  
West African ◽  
Species Density ◽  
Savanna Fires ◽  
Occurrence Patterns

Abstract:We studied the effects of savanna fires on the structure of local ungulate communities in a West African woodland savanna. The distribution of 11 ungulate species over 9−15 burned sites (the number of which increased as burning activity continued during the dry season) and 7−13 unburned sites was compared with a variety of null models or randomized ‘virtual communities’. Five different parameters of community structure were examined: body mass distribution, co-occurrence patterns, species richness, species density and guild dominance. Overall, ungulate species were not randomly distributed over burned and unburned sites. The regular spacing of body masses in the set of species recorded on burned and unburned sites indicated competition, since species similar in body mass are more likely to compete than species of different size. However, co-occurrence patterns on burned sites were random, indicating absence of competition at fine spatial scales due to differential habitat use within the burned landscape. Although the attractiveness of the regrowth on burned sites resulted in higher numbers of ungulates compared with unburned sites, species richness was not different. Grazers were the dominant guild on burned sites, but there were no differences in species richness or species density between grazers and browsers on unburned sites.

Biodiversity among mussels: separating the influence of sizes of mussels from the ages of patches

2007 ◽  
Vol 87 (2) ◽  
pp. 551-557 ◽  
Author(s):  
N.E. O'Connor ◽  
T.P. Crowe
Keyword(s):  
Species Richness ◽  
Habitat Structure ◽  
Size Structure ◽  
Mussel Beds ◽  
Faunal Assemblages ◽  
Lower Abundance ◽  
Invertebrate Assemblages ◽  
Context Dependent

The role of habitat structure in controlling the composition of assemblages has often been studied, but is rarely manipulated so that it is distinguishable from other factors. Differences in habitat structure as determined by differences in mussel size structure may affect the diversity of assemblages associated with mussel beds. Previous studies examining the effect of the size of individual mussels in a patch on the diversity of associated macro-faunal assemblages confounded the age of the patch with the size of the mussels. We manipulated the age of mussel patches and the size of the mussels within them to test experimentally whether the size of mussels influenced the structure of associated assemblages. At one of the two locations considered, the structure of macro-faunal assemblages in patches of larger mussels differed significantly from those in patches of the same age composed of smaller mussels. At this location, the size of mussels did not affect species richness but the abundance and proportion of organisms present differed depending on the size of the mussels. Here patches of larger mussels contained greater numbers of Nematodes and Oligochaetes and a lower abundance of taxa such as Jaera forsmani and Lepidonotus clava. We also found that invertebrate assemblages in general differed between the two locations. The effect of the size structure of mussels, however, varied spatially demonstrating that the effect of habitat structure on the diversity of associated assemblages is context dependent.

scholarly journals The Australasian Virtual Herbarium (AVH) and the Changing Role of Herbaria

2018 ◽  
Vol 2 ◽  
pp. e25866
Author(s):  
Niels Klazenga
Keyword(s):  
New Zealand ◽  
Spatial Scales ◽  
Herbarium Specimens ◽  
Ecological Research ◽  
Collections Management ◽  
Steady Decrease ◽  
Herbarium Data ◽  
Changing Role ◽  
Occurrence Records

Australia’s Virtual Herbarium (AVH) was created in 2001 and developed between 2001 and 2006 with the databasing of the label data of specimens from the Australian Commonwealth, state and territory herbaria. The success of AVH ultimately led to funding for the Atlas of Living Australia (ALA) and in October 2012 AVH was re-launched as part of the ALA infrastructure (http://avh.chah.org.au). Since 2012, some university herbaria have also joined AVH and in June 2017 the New Zealand Virtual Herbarium (NZVH) was integrated, giving rise to the Australasian Virtual Herbarium. The AVH currently holds almost 6.3 million records from 23 Australian and New Zealand herbaria and comprises over 80 per cent of the vouchered occurrence records of Australian plants, algae and fungi in ALA. While no longer at the forefront of the digitisation wave, having been around for so long, AVH can provide valuable insights into how and to what extent herbarium data is used and into the benefits of digitisation for herbaria and natural history collections. Six years of download statistics shows an ever-increasing use of AVH data and a widening of the user base. A far greater proportion of downloaded records is ostensibly used for new uses like ecological research and conservation, than for the traditional uses of herbarium specimen data, systematics and collections management. The last few years have also seen an increase in the use of AVH data in education. Over the years many research articles based on AVH data have been written, mostly at the interface between ecology and systematics, i.e. biogeography and conservation science. With the increase of the types of uses for herbarium data, it becomes important, also for the herbaria themselves, to consider the fitness for purpose of AVH data for uses other than the purpose for which it was collected. It has become apparent that the uncertainty of the latitudes and longitude provided with herbarium specimens is often too great for use in ecological research or conservation and there is a bias in collection density at the bioregion level, which is likely to be more severe at smaller spatial scales. Also, while the demand for vouchered occurrence records is increasing, we have seen a steady decrease in the intake of new specimens by Australian herbaria since the 1980s. This presentation will cover how Australian herbaria use AVH, how other users use AVH and what being part of AVH has meant to Australian herbaria.

Information-seeking to Support Personal and Community Wellbeing: Report of a study of New Zealand Men Using Focus Groups

2016 ◽  
Author(s):  
Peta Wellstead
Keyword(s):  
New Zealand ◽  
Focus Groups ◽  
Support Services ◽  
Information Seeking ◽  
Service Providers ◽  
Structural Constraints ◽  
Health And Wellbeing ◽  
Study Results ◽  
Groupes De Discussion

This paper reports part of an ongoing study exploring the information behaviour of New Zealand men during periods of diminished health and wellbeing. Focus groups were used for this iteration of the study. Results indicate that New Zealand men face both personal and structural constraints to their information-seeking during periods when their health and wellbeing may be compromised. This study highlights that service providers need to develop more effective information delivery mechanisms and support services for men. These services need to be appealing to men and reflect men’s information seeking preferences. The role of LIS professionals in supporting this endeavour is discussed. Cet article présente une étude en cours explorant le comportement informationnel d’ hommes néo-zélandais durant des périodes où leur état de santé et de bien-être est amoindri. Des groupes de discussion ont été utilisés pour cette itération de l'étude. Les résultats indiquent que les hommes en Nouvelle-Zélande font face à des contraintes à la fois  personnelles et structurelles dans leur recherche d'information pendant les périodes où leur santé et leur bien-être peuvent être affaiblis. Cette étude met en évidence le besoin pour les fournisseurs de services de développer des mécanismes de diffusion de l'information plus efficaces et des services de soutien pour les hommes. Ces services doivent être attrayants et refléter les préférences des hommes dans leurs recherches d’information. Le rôle des professionnels de l'information dans le soutien à cette entreprise est discuté.

POLÍTICAS DE ESCALA E A CONFORMAÇÃO DE ESTRATÉGIAS-REDE DAS AÇÕES COLETIVAS NO ESPAÇO SISALEIRO DA BAHIA

GEOgraphia ◽  
2018 ◽  
Vol 19 (41) ◽  
pp. 39
Author(s):  
Agripino Souza Coelho Neto
Keyword(s):  
Political Action ◽  
Spatial Scales ◽  
Spatial Behavior ◽  
Collective Actions ◽  
Collective Behaviors ◽  
Rural Workers ◽  
Scale Levels ◽  
Scale Network ◽  
Comme Point

Resumo: O presente texto pretende analisar o papel das ações coletivas (associações, cooperativas e sindicatos de agricultores) no acionamento e na ativação das escalas geográficas para o desenvolvimento de suas atividades. O estudo foi realizado no Espaço Sisaleiro da Bahia (Brasil), onde um conjunto significativo de associações e cooperativas de agricultores e sindicatos de trabalhadores rurais tem se organizado em torno das escalas espaciais para viabilizar sua ação político-institucional e econômico-produtiva. A ação desses coletivos organizados em rede tem permitido a conformação e o fortalecimento de novas escalas de ação política, como no caso da criação do conselho territorial para viabilização da implantação de políticas de governo. Cooperativas, associações e sindicatos se apoiam nas escalas para compor organizações em diferentes níveis escalares (escala local, escala regional, escala do estado federado e escala nacional), buscando fortalecer seus propósitos e ampliar seu poder de barganha e influência. Analisando o comportamento espacial dessas variadas modalidades de ações coletivas, é possível considerar que elas desenvolvem políticas de escala, ou seja, a escala passa a significar muito mais que uma categoria de análise, mas se torna uma categoria da prática social e política. Nesse sentido, parte-se do pressuposto de que os grupos humanos produzem e tornam efetivas suas próprias escalas visando a alcançar suas metas e organizar seus comportamentos coletivos. Palavras-chave: Escala. Rede. Cooperativismo. Associativismo. Sindicalismo. Espaço Sisaleiro da Bahia. SCALE POLICIES AND THE DEVELOPMENT OF NETWORK STRATEGIES OF COLLECTIVE ACTIONS IN THE SISAL REGION OF BAHIA (BRAZIL)Abstract: This paper aims to analyze the role of collective initiatives of associations, cooperatives and farmers’ unions in the mobilization and activation of geographical scales for the development of their activities. The study was conducted in the Sisal Region of Bahia (Brazil), where a significant number of farmers associations and cooperatives and rural workers’ unions have been organizing their actions around spatial scales to enable their political-institutional and economic-productive influence. The gathering and action of these organized groups in a network have allowed the establishment and strengthening of new scales of political action, as seem in the case of the creation of a territorial council to facilitate the implementation of government policies. Cooperatives, associations, and unions rely on scales to form organizations at different scale levels (local, regional, federal and national scales), seeking to strengthen their performance and increase their bargaining power and influence. After analyzing the spatial behavior of these various forms of collective actions, it’s reasonable to say that they develop scale policies, which means the scale becomes more than a category of analysis, but also a category of social and political practice. In this sense, it’s assumed that human groups produce and utilize the scales in order to reach their goals and organize their own collective behaviors. Keywords: Scale. Network. Cooperativism. Associativism. Syndicalism. Sisal Region of Bahia. POLITIQUES D’ÉCHELLE ET FORMATION DES STRATÉGIES-RÉSEAU DES ACTIONS COLLECTIVES DANS LA RÉGION DU SISAL DE L’ÉTAT DE BAHIA Resumé: Cet article analyse le rôle des actions collectives (associations, coopératives et syndicats d’agriculteurs) dans la prise en compte et l’utilisation des échelles géographiques pour le développement de leurs activités. L’étude a été menée dans la région du sisal à Bahia (Brésil), où un ensemble important d’associations et de coopératives d’agriculteurs et de syndicats de travailleurs ruraux se sont organisés autour d’échelles spatiales pour que puisse être mise en place leur action politique et institutionnelle, économique et productive. L’action de ces groupements organisés en réseaux a permis la conformation et le renforcement de nouvelles échelles d’action politique, comme lors de la création du conseil territorial, pour permettre la mise en œuvre des politiques gouvernementales. Les coopératives, les associations et les syndicats prennent les échelles comme point de départ pour former des organisations à différents niveaux scalaires (échelle locale, échelle régionale, échelle fédérée et échelle nationale), dans le but de renforcer leurs objectifs et d’accroître leur pouvoir de négociation et d’influence. Si nous analysons le comportement spatial de ces diverses formes d’action collective il est possible de considérer qu’ils développent des politiques d’échelle, à savoir l’échelle vient signifier bien plus qu’une catégorie d’analyse, puisqu’elle devient une catégorie de la pratique sociale et politique. En ce sens, on suppose que les groupes humains produisent et rendent efficaces leurs propres échelles pour atteindre leurs objectifs et organiser leurs comportements collectifs. Mots-clés: Échelle. Réseau. Coopérativisme. Associations. Syndicalisme. Région du sisal de l’État de Bahia.

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