Wetlands are viable sinks for nitrate and have also been identified as a source of nitrous oxide, a product of two microbially regulated processes: nitrification and denitrification. Anthropogenic expansion of nitrogen is a leading cause of the eutrophication of water bodies and may also contribute to the deterioration of the ozone layer in the stratosphere. Wetlands ameliorate the quality of water percolating through them, by retaining nutrients and sequestering carbon, and simultaneously enhancing the flora and fauna diversity of these landscapes. Among the many services these wetlands provide, they also alleviate nitrate pollution by attenuating reactive nitrogen from agricultural drainage and ensure the effective reclamation of the wastewater. The literature regarding the viability of wetlands suggests a linear relationship between the removal of nitrogen and its loading rate, thereby suggesting a potential loss of nitrogen removal capacity due to the loss of wetland area. This review discusses the nitrogen removal mechanisms in existing wetlands along with the environmental variables affecting the optimum performance and management of these wetlands, in terms of greenhouse gas retention and biodiversity. Conservation of these wetlands should be contemplated to maintain the world-wide nitrogen cycle and diminish the negative repercussions of surplus nitrogen loading.

Ornamental plant species are mostly grown for aesthetic purposes, for their fruits, vegetables, flowers, and medicinal value. Houses are decorated with various annual and perennial plants. The present study was performed to assess the ornamental plant composition, abundance, and distribution pattern with a special reference to gardening practices/environmental variables in the Rustam Valley, Pakistan. Using quantitative ecological methods, different home gardens were observed at arbitrary intervals. The frequency, relative frequency, density, relative density, and importance values were measured to determine the most frequent and least frequent ornamental plant species in each type of habitat. The initial results showed a total of 43 ornamental plant species belonging to 30 families. Presence-absence data (1, 0) for the 43 ornamental species and 50 stations were analysed using cluster and two-way cluster analyses using the PC-ORD version 5, which resulted in the identification of four different ornamental plant communities. The CANOCO version 4.5 was used to evaluate the environmental and cultural gradients of ornamental plants through the canonical correspondence analysis (CCA). The positions of characteristic plant species in a particular community were confirmed using data attribute plots. The CCA plots of the ornamental and questionnaire data show that irrigation, home size, purpose of cultivation and the use of artificial fertilizers were the main factors affecting various ornamental plant communities. Additionally, further studies should be conducted to examine, conserve, and manage the ornamental plant species diversity and contributions of such species to livelihoods in the study area.