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Temporal Activity (temporal + activity)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Reduced-impact Logging has Little Effect on Temporal Activity of Frugivorous Bats (Chiroptera) in Lowland Amazonia

BIOTROPICA, Issue 3 2009
Steven J. Presley
ABSTRACT Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapajós National Forest, Pará, Brazil. In addition, we evaluated the effects of RIL at a harvest level of 18.7 m3/ha and habitat physiognomy on temporal patterns of activity for these species. Bats were surveyed for four nights at each of 96 sites for a total sampling effort of 64,512 net-m-h. Sites were distributed among four experimental blocks, two blocks of unlogged forest and two blocks of forest subjected to RIL. Half of the sites in each management type were in forest gaps and half were in closed-canopy forest. In general, species exhibited similar patterns of activity, and greater than expected temporal overlap in activity among species. RIL and forest physiognomy had little effect on activity patterns of species. RIL in Amazonia removes fewer trees than do naturally occurring treefalls and such changes in habitat structure do not alter activity patterns of frugivorous bats. Evidence suggests that RIL does not have an appreciable adverse effect on frugivorous bats in Amazonia. RESUMO A exploração madeireira de impacto reduzido é uma opção viável para o uso sustentável de florestas de planícies tropicais, ao passo em que também minimizam os efeitos sobre a biodiversidade local e processos ecossistêmicos. Avaliações dos efeitos de regimes de derrubada de árvores geralmente se baseiam em respostas em nível populacional ou de comunidades e ignoram respostas comportamentais que podem ter consequências críticas em processos ecossistêmicos locais. Muitos dos morcegos neotropicais filostomídeos proporcionam serviços ecossistêmicos associados à polinização e dispersão de sementes, que promovem regeneração de áreas degradadas. Por esse motivo, os efeitos da exploração madeireira de impacto reduzido, sobre essas espécies, devem ter sua importância considerada. Nós avaliamos padrões temporais de atividade, grau de sobreposição temporal de atividade, e dispersão nos picos de atividade de sete espécies de morcegos frugívoros abundantes na Floresta Nacional de Tapajós, Pará, Brasil. Além disso, avaliamos os efeitos da exploração madeireira de impacto reduzido e da fisionomia de habitat (lacunas florestais e locais de dossel fechado) nos padrões temporais de atividade desses morcegos. Em geral, as espécies exibiram padrões de atividade similares, o que resulta em uma sobreposição temporal maior do que a esperada na atividade das espécies. A exploração madeireira de impacto reduzido e a fisionomia florestal tiveram pouco efeito nos padrões de atividades das espécies observadas. A exploração madeireira ora apresentada (2-4 árvores/ha) se propõe a um impacto menor que o associado às quedas naturais de árvores na Amazônia e aparenta não alterar a estrututra dos habitats de forma significativa à atividade das espécies de morcegos aqui estudadas. Consequentemente, não há evidências para acreditar que a exploração madeireira impacto reduzido possua efeitos adversos em espécies abundantes de morcegos frugívoros na Amazônia ou em suas capacidades de continuar a promover a regeneração de áreas degradadas via polinização ou dispersão de sementes. [source]

Effects of stocked trout on native fish communities in boreal foothills lakes

ECOLOGY OF FRESHWATER FISH, Issue 2 2010
Leslie E. Nasmith
Nasmith LE, Tonn WM, Paszkowski CA, Scrimgeour GJ. Effects of stocked trout on native fish communities in boreal foothills lakes. Ecology of Freshwater Fish 2010: 19: 279,289. © 2010 John Wiley & Sons A/S Abstract,,, Ecological effects of stocking nonnative trout into lakes are receiving increased attention, especially in alpine environments. We assessed effects of stocked trout on native forage fishes in the boreal foothills of Alberta (Canada) by comparing fish density, population size structure and spatial and temporal activities in stocked and unstocked lakes over 3 years (2005,2007). The numerically dominant dace (primarily Phoxinus spp.) were larger in stocked lakes, consistent with size-limited predation. Dace were also more crepuscular and concentrated on the lake-bottom in stocked lakes, compared to more daytime activity in the water column in unstocked lakes. There were, however, no demonstrable effects of trout on the abundance of forage fish. The lack of major population-level impacts of stocked trout suggests that current stocking practices, characteristics of boreal foothill lakes (e.g. thermal structure, abundant invertebrates, dense macrophytes) and/or behavioural adjustments of forage fish contribute to healthy native fish populations in our stocked lakes. [source]

Partitioning of temporal activity among desert lizards in relation to prey availability and temperature

AUSTRAL ECOLOGY, Issue 1 2010
CHRISTOPHER E. GORDON
Abstract Partitioning of activity time within ecological communities potentially reduces interspecific competition and increases the number of species that can coexist. We investigated temporal activity in a highly diverse lizard assemblage in the Simpson Desert, central Australia, to determine the degree of partitioning that occurs. Three periods were defined, daytime (sunrise to sunset), early night (sunset to midnight) and late night (midnight to sunrise), and live captures of lizards were tallied for each period during two sampling months (September and November 2007). We also quantified the activity times of potential invertebrate prey and measured ambient temperatures during the different time periods to investigate any associations between these factors and lizard activity. Some 77% of captures of 13 lizard species were made by day, with Ctenotus pantherinus, Egernia inornata (Scincidae) and Nephrurus levis (Gekkonidae) the only species showing extended nocturnal activity. Activity of both species of skink was recorded at temperatures 4°C lower than those for agamid and varanid lizards early in the night, and at temperatures as low as 18,20°C. Surface-active invertebrates differed in composition between time periods and were less abundant during the late night period in the drier of the two sample months (September), but were distributed equally over time in the other month. Termites were active in subterranean galleries at night in September and mostly by day in November, but available at all times on surface/subsurface baits. We conclude that activity is distributed unevenly within this lizard assemblage, with partitioning facilitated by the ready availability of invertebrate prey and by lizards having relatively broad temperature tolerances that, in some cases, permit opportunistic exploitation of resources beyond usual times of activity. [source]

Reduced-impact Logging has Little Effect on Temporal Activity of Frugivorous Bats (Chiroptera) in Lowland Amazonia

BIOTROPICA, Issue 3 2009
Steven J. Presley
ABSTRACT Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapajós National Forest, Pará, Brazil. In addition, we evaluated the effects of RIL at a harvest level of 18.7 m3/ha and habitat physiognomy on temporal patterns of activity for these species. Bats were surveyed for four nights at each of 96 sites for a total sampling effort of 64,512 net-m-h. Sites were distributed among four experimental blocks, two blocks of unlogged forest and two blocks of forest subjected to RIL. Half of the sites in each management type were in forest gaps and half were in closed-canopy forest. In general, species exhibited similar patterns of activity, and greater than expected temporal overlap in activity among species. RIL and forest physiognomy had little effect on activity patterns of species. RIL in Amazonia removes fewer trees than do naturally occurring treefalls and such changes in habitat structure do not alter activity patterns of frugivorous bats. Evidence suggests that RIL does not have an appreciable adverse effect on frugivorous bats in Amazonia. RESUMO A exploração madeireira de impacto reduzido é uma opção viável para o uso sustentável de florestas de planícies tropicais, ao passo em que também minimizam os efeitos sobre a biodiversidade local e processos ecossistêmicos. Avaliações dos efeitos de regimes de derrubada de árvores geralmente se baseiam em respostas em nível populacional ou de comunidades e ignoram respostas comportamentais que podem ter consequências críticas em processos ecossistêmicos locais. Muitos dos morcegos neotropicais filostomídeos proporcionam serviços ecossistêmicos associados à polinização e dispersão de sementes, que promovem regeneração de áreas degradadas. Por esse motivo, os efeitos da exploração madeireira de impacto reduzido, sobre essas espécies, devem ter sua importância considerada. Nós avaliamos padrões temporais de atividade, grau de sobreposição temporal de atividade, e dispersão nos picos de atividade de sete espécies de morcegos frugívoros abundantes na Floresta Nacional de Tapajós, Pará, Brasil. Além disso, avaliamos os efeitos da exploração madeireira de impacto reduzido e da fisionomia de habitat (lacunas florestais e locais de dossel fechado) nos padrões temporais de atividade desses morcegos. Em geral, as espécies exibiram padrões de atividade similares, o que resulta em uma sobreposição temporal maior do que a esperada na atividade das espécies. A exploração madeireira de impacto reduzido e a fisionomia florestal tiveram pouco efeito nos padrões de atividades das espécies observadas. A exploração madeireira ora apresentada (2-4 árvores/ha) se propõe a um impacto menor que o associado às quedas naturais de árvores na Amazônia e aparenta não alterar a estrututra dos habitats de forma significativa à atividade das espécies de morcegos aqui estudadas. Consequentemente, não há evidências para acreditar que a exploração madeireira impacto reduzido possua efeitos adversos em espécies abundantes de morcegos frugívoros na Amazônia ou em suas capacidades de continuar a promover a regeneração de áreas degradadas via polinização ou dispersão de sementes. [source]