Specialized ecological interactions and plant species rarity: The role of pollinators and mycorrhizal fungi across multiple spatial scales

2014 ◽  
Vol 169 ◽  
pp. 285-295 ◽  
Author(s):  
Ryan D. Phillips ◽  
Rod Peakall ◽  
Michael F. Hutchinson ◽  
Celeste C. Linde ◽  
Tingbao Xu ◽  
...  
2006 ◽  
Vol 52 (1) ◽  
pp. 29-53 ◽  
Author(s):  
Salit Kark ◽  
Berndt J. van Rensburg

Areas of environmental transition, where ecological communities coincide, are sometimes termed ecotones. These regions often correspond with sharp environmental gradients. Ecotones occur at multiple spatial scales, ranging from transitions between biomes to local small-scale transitions. In recent years ecotones have received increasing scientific attention after being neglected for years, as studies historically often focused on distinct communities. However, it is still debatable whether these transitional regions are speciation and biodiversity hotspots that deserve special conservation interest or are actually areas that hold marginal populations that depend on other parts of the range for the maintenance of their biodiversity and therefore should not deserve primary investment. This paper discusses some of the recent advancements in our understanding of the role of ecotones in ecology, evolution, and conservation.


2016 ◽  
Vol 38 (4) ◽  
pp. 381 ◽  
Author(s):  
Alan B. C. Kwok ◽  
David J. Eldridge

Plant-resident arthropods are closely tied to the distribution of their hosts across multiple spatial scales. Shrubs provide habitat for a range of arthropods, and variations within shrubland ecosystems may affect arthropod communities. We examined the role of shrub species and density in structuring arthropod communities in an encroached Australian woodland using two common and widespread shrub species, Turpentine (Eremophila sturtii) and Silver Cassia (Senna artemisioides subsp. filifolia). We found five times more arthropods (Psocoptera, Collembola and Hemiptera) on Eremophila compared with Senna. Furthermore, Psyllidae were found only on Eremophila. In total we recorded 39 Hemipteran species; 13 from Eremophila, 16 from Senna and 10 common to both shrub species. Each shrub species supported a unique arthropod assemblage, even though they grow in close proximity (<15 m). In contrast, we found limited effects of fine-scale plant density, with plants growing in low and high density supporting similar arthropod communities. Our study indicated that isolated shrubs in these woodlands support a variety of arthropods, and shrub species is a more important driver of arthropod community structure than fine-scale density.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yann Hautier ◽  
Pengfei Zhang ◽  
Michel Loreau ◽  
Kevin R. Wilcox ◽  
Eric W. Seabloom ◽  
...  

Abstract Eutrophication is a widespread environmental change that usually reduces the stabilizing effect of plant diversity on productivity in local communities. Whether this effect is scale dependent remains to be elucidated. Here, we determine the relationship between plant diversity and temporal stability of productivity for 243 plant communities from 42 grasslands across the globe and quantify the effect of chronic fertilization on these relationships. Unfertilized local communities with more plant species exhibit greater asynchronous dynamics among species in response to natural environmental fluctuations, resulting in greater local stability (alpha stability). Moreover, neighborhood communities that have greater spatial variation in plant species composition within sites (higher beta diversity) have greater spatial asynchrony of productivity among communities, resulting in greater stability at the larger scale (gamma stability). Importantly, fertilization consistently weakens the contribution of plant diversity to both of these stabilizing mechanisms, thus diminishing the positive effect of biodiversity on stability at differing spatial scales. Our findings suggest that preserving grassland functional stability requires conservation of plant diversity within and among ecological communities.


2002 ◽  
Vol 29 (4) ◽  
pp. 566-577 ◽  
Author(s):  
THOMAS J. STOHLGREN ◽  
GENEVA W. CHONG ◽  
LISA D. SCHELL ◽  
KELLY A. RIMAR ◽  
YUKA OTSUKI ◽  
...  

2019 ◽  
Vol 612 ◽  
pp. 29-42 ◽  
Author(s):  
NR Evensen ◽  
C Doropoulos ◽  
KM Morrow ◽  
CA Motti ◽  
PJ Mumby

GEOgraphia ◽  
2018 ◽  
Vol 19 (41) ◽  
pp. 39
Author(s):  
Agripino Souza Coelho Neto

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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