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Although tropical rainforests preserve high levels of biodiversity, they are among the most threatened ecosystems globally due to large-scale fragmentation as a result of anthropogenic activities. Overall, fast human-driven habitat destruction is suspected to be one of the major causes of species extinction. The mosaic of vegetation types, which contributes to the incredible diversity of the tropics is highly impacted by large-scale fragmentation. The main causes of such habitat fragmentation are selective logging for valuable timber and agricultural clearance. The knowledge of the short and long-term effects of removing selected species in the tropical rainforests are scarce and need to be further investigated. Some studies about the effects of tropical forest disturbance in the short term have been conducted, but in the long term, there is limited knowledge. In this paper, I consider a system of coupled ordinary differential equations (ODEs) that modelled the dynamics of tropical rainforest subject to selective logging to understand how and why weeds and vine displace and limit tree species. From the empirical data collected on canopy height and plant diversity and the model proposed, I have the evidence of a decreasing tree diversity in tropical forests subject to management in comparison with to the same but untouched forests. [ABSTRACT FROM AUTHOR]

Abstract: Many organisms are threatened by global climate change, but as sessile organisms, plants are particularly vulnerable. Unable to individually move to areas with more suitable conditions as the climate changes, plants must instead rely on their seeds dispersing far and often in order to migrate fast enough to keep pace with the changing climate. The fragmentation of natural landscapes by clearing for agricultural or urban development, or a species’ requirement for particular soil types or topography, makes this migration even more problematic. The likelihood of a plant species persisting will thus depend on factors such as the rate of climate change, the degree of landscape fragmentation, and also the plant species’ lifecycle, seed production, dispersal, and establishment. This paper presents a dynamic model, called PPunCC (Plant Persistence under Climate Change), that represents the important factors and processes likely to affect a plant species’ capacity to migrate across a landscape fast enough to avoid extinction. We use the model to show that creating large-scale corridors that increase the connectivity of fragmented landscapes through targeted restoration could help species migrate naturally and find suitable environments in new climates. We also examine the effect of varying the key point of vulnerability within its lifecycle between juvenile establishment, adult mortality or seed production and conclude that this has a relatively minor effect on the prognosis for the plant and does not affect the predicted benefits of restoration. [Copyright &y& Elsevier]

A nonlinear n-population metapopulation model, which can describe the nonlinear relationship between one species and other species or between one species and the habitat, is presented in this paper. By simulation and mathematics analysis, we discover that species possess an ability to control or avoid extinction during habitat destruction. Any species in n-population metapopulation can increase (decrease) the influence of habitat destruction if it agrees (disagrees) with the environment, and it also can increase (decrease) the proportion of sites occupied by all species by harmonizing (not harmonizing) with the other species. [Copyright &y& Elsevier]