Final answer:
A metacommunity is a network of local communities connected by dispersal of species, which also considers geographical significance of space between habitats. Therefore, the correct answer includes both the network aspect and the geographical elements, making options 'c' and 'd' accurate.
Step-by-step explanation:
A metacommunity is best described as a network of local communities connected by dispersal of one or more species. This concept relies on the understanding that populations of different species are often not isolated but interact across different habitats. These interactions are crucial for maintaining biodiversity, speciation, and ecological dynamics. The metacommunity framework has gained significant importance in ecology, integrating community structure and species distribution patterns. Two main types of metapopulation models, closely related to metacommunities, highlight this dynamic structure: the mainland-island metapopulation and metapopulations with similarly-sized populations.
In the mainland-island model, a large source population (mainland) sends out emigrants to smaller, more vulnerable populations (islands), assisting their persistence and introducing genetic diversity. The second type involves similar-sized populations where individuals move between populations, ensuring species survival despite local extinctions. Therefore, in the context of the provided question, the answer is 'c. A network of local communities connected by dispersal of one or more species' and 'd. Both A and C' since metacommunities relate to both the dispersal among habitats and the geographical significance of space and distance between these habitats.