Read the following passage.
The Atsinanana region of Madagascar is celebrated for its exceptional biodiversity and high levels of endemism. It provides critical habitats for numerous rare species, including several unique reptiles and amphibians. The total area of this study region is 390,000 km2390,000\text{ km}^2390,000 km2. The actual land area of the region is 312,000 km2312,000\text{ km}^2312,000 km2, as approximately one-fifth of the region consists of rivers, lakes, and swampy wetlands.
In December 1998, dense primary rainforest covered 56.4% of the actual land area.
In December 2018, dense primary rainforest covered 41.4% of the actual land area.
Agricultural expansion, logging, and habitat fragmentation have severely reduced and divided the forest canopy, threatening populations of endemic, tree-dwelling geckos. Conservationists frequently attempt to estimate the population sizes of these small nocturnal geckos using the capture-mark-recapture method. However, researchers have noted that this technique often yields highly unreliable estimates when applied to populations living in the high, complex canopy layer.
Use the information in the passage and your own knowledge to answer the following questions.
The percentage of forest cover in this region decreased between December 1998 and December 2018. Calculate the mean loss of forest cover in km2\text{km}^2km2 per week during this 20-year period. Show your working.
Suggest why the capture-mark-recapture method can produce unreliable population estimates for small, arboreal geckos in dense, high rainforest canopies.