Effect of habitat fragmentation by properties on the Costa Rican mammal diversity and abundance

The student from HAS University of Applied Sciences (Netherlands), Bas van der Zeijden has already finished his study to compare the mammals abundance between nature Reserve and other properties in Ojochal. He invited the neighbors that participate on this study and shared the results with all of them on a presentation at Reserva Playa Tortuga.

Why is this study important?

Mammals need a large amount of habitat for foraging and reproducing, Agoutis have a smaller habitat (2 km2) and ocelots a way larger habitat (50 km2), if not more. Despite the size,  all of these mammals are vulnerable to habitat fragmentation and loss, such as logging, construction of roads and properties. But what is the effect of properties here in in Ojochal? What does it do with the size and abundance of the mammals.

In some of the forest, mammals are responsable for 66% of the seed disperse, playing a vital role in the seed dispersal of the rainforests. Also, by eating plants, the will create space for other plants. Or they will increase the biodiversity by eating the dominant plants, leaving space for the other less dominant species.

Camera locations:

Results:

• 13 different species
• 7 different mammals at the reserve
• 11 different mammals at the properties

• 343 mammals captured on camera
• Ridgeline is the only property with a higher abundance than the reserve
• Farmland has the lowest relative abundance
• The agouti has the highest abundance with 52,48%
• Primary forest has the highest biodiversity
• The maintained garden has the lowest biodiversity

On Bas’s words the study was too short to draw a significant conclusion, but there are some indications. For example:

• The primary forest on slope and the ridgeline have a higher biodiversity, compared to the reserve, probably because of the big primary forests near the property, and the low human disturbance
• The old cashew plantation has a low abundance and number of species. Some possible causes are: no food, disturbance, etc.
• The creek has a lower biodiversity,  and that might be because of high pet activity, gardeners or a position too close to the creek
• The maintained garden has a low biodiversity, which is the most logical result, since the garden has no forest, a high human and pet activity.
• The farmland has almost no mammals, probably for the presence of traveler and no suitable vegetation and human activity