Viewpoint: Trend Assessment by Similarity: A Demonstration

Ratliff, Raymond D.

doi:10.2307/4002270

Cited by 13 publications

(12 citation statements)

References 3 publications

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“…SG were consumed more frequently in domestic cattle absence, whereas when domestic cattle was presented, the ingest of this lifeform decreases and the intake of HD and Gr increases (Figure 2). This agrees with what was before described about the guanaco diet in Tierra del Fuego, 8,16,19,29,31,32 in arid and semiarid areas of the Patagonia. [34][35][36][37][38] Table 2 Comparison of the vegetal composition of the three studied communities, using the Sörensen Index.…”

Section: Resultssupporting

confidence: 92%

Guanacos’ and domestic livestock’s summer diets comparison in ecotone of “Tierra del Fuego” (Argentina)

Mg¹,

As²,

Mo³

et al. 2018

BIJ

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At present, it is believed that the population of guanacos has increased in the "Isla Grande de Tierra del Fuego", arising a conflict with livestock and forestry activities. The aim of this study was to evaluate the use of the guanaco's food resources, taking into account the presence of different types of domestic livestock, in order to provide a tool which will enable the evaluation of environmental management projects. We conducted the study in different areas, considering the presence/absence of domestic livestock and of guanaco. The diet was analyzed by identifying botanical remains present in the pretreated feces. The relative frequencies of ingested taxa were obtained and analyzed according to their functional groups, being the soft, herbaceous and graminoid grasses the most consumed, where the soft grasses were the most frequently ingested. Tree species only appear in diets of guanacos, in a low frequency, compared to other forms of life. In the case of soft grasses, forbs and Graminoides, the diets differ according to ingested species and intake frequency. These results allow us to establish that the guanaco selects the items to be consumed, changing its diet based on the presence of other herbivores, and has a trophic overlap with domestic livestock, mainly with sheep.

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Section: Resultssupporting

confidence: 92%

Guanacos’ and domestic livestock’s summer diets comparison in ecotone of “Tierra del Fuego” (Argentina)

Mg¹,

As²,

Mo³

et al. 2018

BIJ

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“…If the SI coefficient is higher than 0.75 it is considered to reflect very high similarity, values in the range between 0.51 and 0.75 reflect high similarity, and values between 0.26 and 0.50 describe moderate similarity. Low similarity is described by values below 0.25 (Ratliff 1993). We calculated similarity for five groups of plants: total, exotic, dune obligate, grassland and mesic species.…”

Section: Data Analysesmentioning

confidence: 99%

Temporal and spatial changes in plant dune diversity in urban resorts

Faggi

Dadon

2011

J Coast Conserv

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We investigated the temporal and spatial changes in the floristic composition and abundance in sand dunes along a coastal strip in the province of Buenos Aires (Argentina). Firstly, we analysed changes over a span of 70 years, comparing 41 of our own inventories carried out in 14 beach resorts in 2005-2006 with 18 inventories made in the first half of the XXth century (1930)(1931)(1932)(1933)(1934)(1935)(1936)(1937)(1938)(1939)(1940) in the same study area. We grouped sampled plots into four categories for comparison, taking into account the time period (1930-1940 or 2005-2006) and location at each end of the surveyed coastal strip in the northern or southern 'tourist' sectors. Secondly, we analysed the effect of afforestation with exotic trees on extant sand dune vegetation for the period 2005-2006. A total of 74 plant inventories were carried out in afforested and natural dunes at the same resorts. In both comparisons we contrasted plant richness, percentage plant cover, similarity and diversity. A cluster analysis was used to classify categories taking into account plant abundance and composition. Significant differences in total diversity were observed between sampling years, suggesting an increase in diversity at the present time due to urbanization and recreation related activities. Nevertheless, no single exotic plant species was clearly dominant across the sampled sites, suggesting that these coastal areas are, up to now, resistant to alien invasion. Diversity indexes discriminated by plant groups indicating different habitat conditions and exotics were shown to be more sensitive to existing changes than to total richness and cover.

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“…Una baja contribución al SI indica completa falta de similitud (no hay especies o valores en común) por otro lado, una contribución alta al SI indica completa similitud (todas las especies o valores son comunes) y por lo tanto, un tipo de planta específica o especie es usada según la disponibilidad (Ratliff, 1993).…”

Section: Methodsunclassified

“…Low contribution to SI indicate complete lack of similarity (there are no common species or values) whereas a high contribution to SI indicate complete similarity (all species or values are common) and therefore a specific plant type or species is used according to its availability (Ratliff, 1993).…”

Section: Methodsmentioning

confidence: 99%

Utilización Del Forraje Y Selección De La Dieta Por Cabras Pastando en Un Matorral Sarcocaulescente en El Noroeste De México

Armenta-Quintana¹,

Ramírez-Orduña²,

Ramírez-Lozano³

2011

RCHSCFA

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RESUMENEl agostadero sarcocaulescente es representativo del desierto Sonorense en Baja California Sur, México, de su flora, 92 % son arbustos y 23 % son especies endémicas, sin embargo, el impacto ecológico de la producción animal es desconocido. Los objetivos de este estudio fueron determinar y comparar durante dos años la preferencia y utilización de especies de plantas por caprinos en pastoreo. La colecta de datos de campo se llevó a cabo de junio de 2006, a junio de 2008. Los datos de composición botánica de la dieta y del área de estudio se emplearon para estimar los índices de preferencia y similitud. Se detectaron 78 especies, de las cuales los caprinos utilizaron 41; en cada muestreo, los animales utilizaron de 10 a 24 especies. El índice de similitud medio fue 26 % (16-32 %), la preferencia y la utilización fueron variables entre muestreos. La preferencia no estuvo acorde con la similitud. Este patrón de conducta alimenticia puede ser indicativo de una estrategia conservativa de utilización del forraje por los caprinos. ABSTRACTSarcocaulecent scrubland is representative of the Sonoran Desert of Baja California Sur, Mexico. In this area 92 % of its flora is shrubs and 23 % of these are endemic species, however, the ecological impact of animal production is unknown. The objectives of this study were to determine and to compare during two years the preference and use of plant species by grazing goats. Data field collections were done from June 2006 through June 2008. Botanical composition of diet and the study area data sets were used to estimate preference and similarity indices. In the studied site total plant species were 78 and goats utilized 41 throughout the study, in each collection date goats utilized 10 to 24 species. Mean similarity index was 26 % (16 to 32 %), both preference and utilization were highly variable between collection dates for each plant species. Preference by goats was not in accordance with similarity. This pattern of feeding behavior may indicate a conservative strategy of forage utilization by goats. PALABRAS CLAVE: Cabras enpastoreo, desierto sonorense, utilización de plantas, preferencia de forrajes, hábitos alimenticios KEY WORDS: Ranggoats, sonoran desert, plant utilization, forage preference, feeding behavior.

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Viewpoint: Trend Assessment by Similarity: A Demonstration

Cited by 13 publications

References 3 publications

Guanacos’ and domestic livestock’s summer diets comparison in ecotone of “Tierra del Fuego” (Argentina)

Guanacos’ and domestic livestock’s summer diets comparison in ecotone of “Tierra del Fuego” (Argentina)

Temporal and spatial changes in plant dune diversity in urban resorts

Utilización Del Forraje Y Selección De La Dieta Por Cabras Pastando en Un Matorral Sarcocaulescente en El Noroeste De México

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