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Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept
Robert D. Davic
Ecology and Society , 2003,
Abstract: The concept of the "keystone species" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups at lower trophic levels that are structured by competition for a limited resource. The a priori prediction of keystone species has applied value for the conservation of natural areas.
Cultural Keystone Species: Implications for Ecological Conservation and Restoration  [cached]
Ann Garibaldi,Nancy Turner
Ecology and Society , 2004,
Abstract: Ecologists have long recognized that some species, by virtue of the key roles they play in the overall structure and functioning of an ecosystem, are essential to its integrity; these are known as keystone species. Similarly, in human cultures everywhere, there are plants and animals that form the contextual underpinnings of a culture, as reflected in their fundamental roles in diet, as materials, or in medicine. In addition, these species often feature prominently in the language, ceremonies, and narratives of native peoples and can be considered cultural icons. Without these "cultural keystone species," the societies they support would be completely different. An obvious example is western red-cedar (Thuja plicata) for Northwest Coast cultures of North America. Often prominent elements of local ecosystems, cultural keystone species may be used and harvested in large quantities and intensively managed for quality and productivity. Given that biological conservation and ecological restoration embody human cultures as crucial components, one approach that may improve success in overall conservation or restoration efforts is to recognize and focus on cultural keystone species. In this paper, we explore the concept of cultural keystone species, describe similarities to and differences from ecological keystone species, present examples from First Nations cultures of British Columbia, and discuss the application of this concept in ecological restoration and conservation initiatives.
The keystone species concept: a critical appraisal
Henry Eden W Cottee-Jones,Robert J. Whittaker
Frontiers of Biogeography , 2012,
Abstract: The keystone concept has been widely applied in the ecological literature since the idea was introduced in 1969. While it has been useful in framing biodiversity research and garnering support in conservation policy circles, the terminology surrounding the concept has been expanded to the extent that there is considerable confusion over what exactly a keystone species is. Several authors have argued that the term is too broadly applied, while others have pointed out the technical and theoretical limitations of the concept. Here, we chart the history of the keystone concept’s evolution and summarise the plethora of different terms and definitions currently in use. In reviewing these terms, we also analyse the value of the keystone concept and highlight some promising areas of recent work.

ZHANG Zhi-Dong,ZANG Run-Guo,

植物生态学报 , 2007,
Abstract: Aims Our major objectives were to 1)identify keystone species within the context of functional groups,2)develop potential distributional predictions for keystone species using ecological niche model,3)confirm factors determining potential distributions of keystone species,and 4)test if the performances of ecological niche model are better than those of a random model and differ in predicting different keystone species.Methods Based on the investigation of 135 plots in a natural tropical forest landscape,we classified woody plant functional groups based on successional status and potential maximum height.Keystone species within each functional group were identified using a dominance index(DI).We used the genetic algorithm for rule-set prediction(GARP)to estimate the keystone species' potential distribution and then used the receiver operating characteristics to evaluate predictive performance.Applying multiple linear regression analysis,we identified major factors determining potential distributions of keystone species.Important findings Identification of keystone species within pioneer species,climax shrub and emergent tree functional groups was clearer than within climax subcanopy and climax canopy tree functional groups.Generally,among the eight keystone species,pioneer species Melastoma sanquiueum,Aporosa chinensis and Liquidambar formosana(but not Adinandra hainanensis)have high probability of occurrence in the north,west and southwest regions of Bawangling.However,climax species Psychotria rubra,Ardisia quinquegona and Castanopsis hainanensis(but not Pinus merkusii)have high probability of occurrence in the central,southeast and south regions.Minimum and maximum temperature,mean annual temperature and precipitation,aspect and altitude were the key factors determining potential distributions of keystone species.Evaluation of GARP model's performance indicated excellent predictive ability of all eight keystone species' distribution.This study suggests the DI method is more suitable to identify keystone species within woody plant functional groups in which a single or a few species are dominant.Findings will assist decision makers in planning conservation and management policies in tropical rainforest areas.
Large extinctions in an evolutionary model: The role of innovation and keystone species  [PDF]
Sanjay Jain,Sandeep Krishna
Physics , 2001, DOI: 10.1073/pnas.032618499
Abstract: The causes of major and rapid transitions observed in biological macroevolution as well as in the evolution of social systems are a subject of much debate. Here we identify the proximate causes of crashes and recoveries that arise dynamically in a model system in which populations of (molecular) species co-evolve with their network of chemical interactions. Crashes are events that involve the rapid extinction of many species and recoveries the assimilation of new ones. These are analyzed and classified in terms of the structural properties of the network. We find that in the absence of large external perturbation, `innovation' is a major cause of large extinctions and the prime cause of recoveries. Another major cause of crashes is the extinction of a `keystone species'. Different classes of causes produce crashes of different characteristic sizes.
Identifying Keystone Species in the Human Gut Microbiome from Metagenomic Timeseries Using Sparse Linear Regression  [PDF]
Charles K. Fisher, Pankaj Mehta
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102451
Abstract: Human associated microbial communities exert tremendous influence over human health and disease. With modern metagenomic sequencing methods it is now possible to follow the relative abundance of microbes in a community over time. These microbial communities exhibit rich ecological dynamics and an important goal of microbial ecology is to infer the ecological interactions between species directly from sequence data. Any algorithm for inferring ecological interactions must overcome three major obstacles: 1) a correlation between the abundances of two species does not imply that those species are interacting, 2) the sum constraint on the relative abundances obtained from metagenomic studies makes it difficult to infer the parameters in timeseries models, and 3) errors due to experimental uncertainty, or mis-assignment of sequencing reads into operational taxonomic units, bias inferences of species interactions due to a statistical problem called “errors-in-variables”. Here we introduce an approach, Learning Interactions from MIcrobial Time Series (LIMITS), that overcomes these obstacles. LIMITS uses sparse linear regression with boostrap aggregation to infer a discrete-time Lotka-Volterra model for microbial dynamics. We tested LIMITS on synthetic data and showed that it could reliably infer the topology of the inter-species ecological interactions. We then used LIMITS to characterize the species interactions in the gut microbiomes of two individuals and found that the interaction networks varied significantly between individuals. Furthermore, we found that the interaction networks of the two individuals are dominated by distinct “keystone species”, Bacteroides fragilis and Bacteroided stercosis, that have a disproportionate influence on the structure of the gut microbiome even though they are only found in moderate abundance. Based on our results, we hypothesize that the abundances of certain keystone species may be responsible for individuality in the human gut microbiome.
Bottom-Up Regulation of Capelin, a Keystone Forage Species  [PDF]
Alejandro D. Buren, Mariano Koen-Alonso, Pierre Pepin, Fran Mowbray, Brian Nakashima, Garry Stenson, Neil Ollerhead, William A. Montevecchi
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087589
Abstract: The Northwest Atlantic marine ecosystem off Newfoundland and Labrador, Canada, has been commercially exploited for centuries. Although periodic declines in various important commercial fish stocks have been observed in this ecosystem, the most drastic changes took place in the early 1990s when the ecosystem structure changed abruptly and has not returned to its previous configuration. In the Northwest Atlantic, food web dynamics are determined largely by capelin (Mallotus villosus), the focal forage species which links primary and secondary producers with the higher trophic levels. Notwithstanding the importance of capelin, the factors that influence its population dynamics have remained elusive. We found that a regime shift and ocean climate, acting via food availability, have discernible impacts on the regulation of this population. Capelin biomass and timing of spawning were well explained by a regime shift and seasonal sea ice dynamics, a key determinant of the pelagic spring bloom. Our findings are important for the development of ecosystem approaches to fisheries management and raise questions on the potential impacts of climate change on the structure and productivity of this marine ecosystem.
Integrating Traditional Ecological Knowledge and Fisheries Management in the Torres Strait, Australia: the Catalytic Role of Turtles and Dugong as Cultural Keystone Species  [cached]
James R. A. Butler,Alifereti Tawake,Tim Skewes,Lavenia Tawake
Ecology and Society , 2012, DOI: 10.5751/es-05165-170434
Abstract: In many developing regions of Melanesia, fishers' traditional ecological knowledge (TEK) has been integrated with western science and management knowledge (SMK) to generate innovative and effective fisheries management. Previous research suggests that three factors initiate this process: depleted fishery stocks, limited SMK, and ownership of resources by local communities. In other contexts the extent of power-sharing through comanagement, and the cultural significance of species may also be important determinants of knowledge integration. Here we assess the role of these factors in the application of TEK in the Torres Strait Islands, Australia, where commercial and subsistence fisheries are fundamental to the Indigenous Melanesian culture and livelihoods. In 2009 we surveyed fishery managers and scientists who revealed that TEK had only been recently and sparingly applied in four fisheries (turtle, dugong, lobster, and hand collectables), and only two of the seven species concerned had a combination of depleted stocks, low SMK, and high community ownership. Instead, comanagement characteristics and the cultural value of species were the primary determinants of TEK application. We suggest that turtles and dugong are cultural keystone species that simultaneously provide important ecosystem services to both islanders' livelihoods and international conservation interests. Combined with their ecological scale these species have catalyzed comanagement between indigenous and government stakeholders, precipitating the application of TEK in other fisheries of lesser cultural importance. We discuss modifications to governance required to enable knowledge integration to evolve further through adaptive comanagement, and its role in enhancing fisheries management and thus the resilience of the Torres Strait social-ecological system. Our study highlights the potential utility of cultural keystone species in stimulating cross-cultural resource governance in developed economies such as Australia.
Bioinformatic analysis of ESTs collected by Sanger and pyrosequencing methods for a keystone forest tree species: oak
Saneyoshi Ueno, Grégoire Le Provost, Valérie Léger, Christophe Klopp, Céline Noirot, Jean-Marc Frigerio, Franck Salin, Jér?me Salse, Michael Abrouk, Florent Murat, Oliver Brendel, Jérémy Derory, Pierre Abadie, Patrick Léger, Cyril Cabane, Aurélien Barré, Antoine de Daruvar, Arnaud Couloux, Patrick Wincker, Marie-Pierre Reviron, Antoine Kremer, Christophe Plomion
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-650
Abstract: We generated 145,827 sequence reads from 20 cDNA libraries using the Sanger method. Unexploitable chromatograms and quality checking lead us to eliminate 19,941 sequences. Finally a total of 125,925 ESTs were retained from 111,361 cDNA clones. Pyrosequencing was also conducted for 14 libraries, generating 1,948,579 reads, from which 370,566 sequences (19.0%) were eliminated, resulting in 1,578,192 sequences. Following clustering and assembly using TGICL pipeline, 1,704,117 EST sequences collapsed into 69,154 tentative contigs and 153,517 singletons, providing 222,671 non-redundant sequences (including alternative transcripts). We also assembled the sequences using MIRA and PartiGene software and compared the three unigene sets. Gene ontology annotation was then assigned to 29,303 unigene elements. Blast search against the SWISS-PROT database revealed putative homologs for 32,810 (14.7%) unigene elements, but more extensive search with Pfam, Refseq_protein, Refseq_RNA and eight gene indices revealed homology for 67.4% of them. The EST catalogue was examined for putative homologs of candidate genes involved in bud phenology, cuticle formation, phenylpropanoids biosynthesis and cell wall formation. Our results suggest a good coverage of genes involved in these traits. Comparative orthologous sequences (COS) with other plant gene models were identified and allow to unravel the oak paleo-history. Simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) were searched, resulting in 52,834 SSRs and 36,411 SNPs. All of these are available through the Oak Contig Browser http://genotoul-contigbrowser.toulouse.inra.fr:9092/Quercus_robur/index.html webcite.This genomic resource provides a unique tool to discover genes of interest, study the oak transcriptome, and develop new markers to investigate functional diversity in natural populations.The distribution of adaptive genetic variation has become of upmost importance in domesticated and wild tree species for th
On the nature of keystone species  [cached]
Jerome Vanclay
Ecology and Society , 1999,
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