Why are small and disconnected habitat patches difficult for some species to survive in?

Small and disconnected habitat patches, a result of habitat fragmentation, are difficult for many species to inhabit for several key reasons:

• Demographic and Genetic Risks: Individual fragments may be too small to support a viable population. This leads to increased risks of inbreeding among survivors and makes it harder for individuals to find mates, threatening the long-term survival of the species.12
• Movement and Isolation: As the distance between patches increases, mobile species face higher risks of predation or mortality while traversing the "matrix" (the area between patches). For immobile species, such as plants, or those unable to cross the matrix, fragmentation acts as a barrier that hinders reproduction by preventing individuals from meeting.3
• Environmental Alterations: Fragmentation can change critical abiotic factors within the remaining patches, such as temperature, wind exposure, soil nutrients, and water availability, which may render the environment unsuitable for species adapted to specific conditions.3
• Reduced Resilience: Smaller patches often lack the complexity needed to recover from disturbances, making the populations within them more vulnerable to local extinction.1