Disturbance is an important phenomenon affecting plant lives and shaping plant strategies in disturbed habitats. A variety of ecological concepts on individual plant response to injury has been proposed for specific natural ecosystems or growth forms. In central Europe, man-made habitats are often cases of disturbed places, so the aim of the thesis was to apply four chosen concepts on them. The thesis is composed of four original studies performed in two model ecosystems: recurrently disturbed ruderal place and regularly mown central European meadow. The occupying of the aboveground space after a disturbance event was studied here either as renovation of biomass or architecture. Regenerative strategies in herbs occupying disturbed habitats were described and confronted with concepts proposed originally for ecosystems subjected to natural disturbance regimes.

Made available in DSpace on 2017-07-10T17:47:55Z (GMT). No. of bitstreams: 1 Cristiani_Cavilhao.pdf: 435376 bytes, checksum: d7bdf3578b70b41b4f8a307fbfe5b476 (MD5) Previous issue date: 2013-09-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / It was aimed with this study to evaluate the different levels effect of feed restriction on performance, intake, digestibility and feeding behavior of feedlot finished lambs, besides the economic viability of this feed management type . For this, 24 Santa Inês male lambs were used, to 20.00 ± 0.32 kg body weight distributed in an entirely randomized design in four different treatments. The experiment was divided into periods of 64 days each, in the first called restriction, the animals were assigned to treatments: no restriction (ad libtum intake with 10% leftovers), restriction of 20, 40 and 60 % in relation to intake of the control treatment. In the second period, called refeeding period, the diet was offered ad libitum to all animals in the experiment. Data were subjected to the variance analysis F test and when significant differences were detected, the regression analysis was used to study the food restriction levels. All statistical procedures were evaluated at 5 % probability. Feed restriction affected negatively the animals performance in all periods . There was a linear decrease in the intake of dry matter and nutrients throughout the experiment . No effects of dietary restriction on eating behavior were identified, except for time spent with feeding that was significantly reduced . The apparent digestibility of dry matter and nutrients did not differ statistically , except in the fiber digestibility in neutral detergent that linearly increased in the restrictive period with the imposed restriction levels . The food restriction management is economically viable in feedlot lambs production for 128 days / Objetivou-se com este trabalho avaliar o efeito de diferentes níveis de restrição alimentar sobre o desempenho, consumo, digestibilidade e comportamento ingestivo de cordeiros terminados em confinamento, além da viabilidade econômica deste tipo de manejo alimentar. Para tanto, foram utilizados 24 cordeiros machos Santa Inês, aos 20,00 ± 0,32 kg de peso corporal, distribuídos em delineamento inteiramente casualizado em quatro tratamentos distintos. O experimento foi dividido em 2 períodos de 64 dias cada, no primeiro chamado de restrição, os animais foram distribuídos nos tratamentos: sem restrição (consumo ad libtum com 10% de sobras), restrição de 20, 40 e 60% em relação ao consumo do tratamento controle. No segundo período, chamado de período de realimentação, a dieta foi ofertada ad libitum á todos os animais do experimento. Os dados foram submetidos ao teste F de análise de variância e quando detectadas diferenças significativas, a análise de regressão foi utilizada para estudo dos níveis de restrição alimentar. Todos os procedimentos estatísticos foram avaliados a 5% de probabilidade. A restrição alimentar afetou de maneira negativa o desempenho dos animais em todos os períodos avaliados. Houve redução linear no consumo de matéria seca e de nutrientes durante todo o experimento. Não foram identificados efeitos da restrição alimentar sobre o comportamento ingestivo, exceto no tempo despendido com alimentação que reduziu de forma significativa. A digestibilidade aparente da matéria seca e nutrientes não diferiu estatisticamente, senão na digestibilidade da fibra em detergente neutro que aumentou linearmente no período restritivo com os níveis de restrição imposta. O manejo de restrição alimentar é economicamente viável na produção de cordeiros confinados por 128 dias