Monteverde The Study of birds and their relationships in Monteverde. What started the interests in bird life in Monteverde The first biologists to enter this region where ornithologists William Buskirk and George Powell. – They where attracted by the low stature of the cloud forest, which made research on mixed-species flocks more tractable than in tall lowland forests. – Most research focuses in on autecological studies and bird-plant interaction studies (now a days most studies focus on plant bird interactions due to changes in in scientific fashion). Reasons Why Monteverde is so Attractable 1) Unusual Behavior – many species of birds exhibit bizarre behavior patterns. 2) Abundance and Ease of Study – most species have large populations and occur close to or around ground level, making them easier to study. 3) Changes in Avifauna Small Spatial Scales – one striking feature is the turn over of fauna from one life zone to the next. In a short walk one can pass through six life zones and see the different avian. 4) Dramatic Coloration – many scientists and bird enthusiasts are attracted to the aesthetic appeal of the avian community (i.e. the Resplendent Quetzal). 5) Alluring Setting – agreeable climate, spectacular views, bilingual populace, and international expatriates that welcomes biologists draws many from ornithologists community. Distribution, Species Richness, and Diversity What makes Monteverde so unique is that most other areas of Costa Rica have either dry or wet forest fauna plus some North American migrants, but Monteverde has all three types. Three Principle Regions of Monteverde. – 1) The Guanacaste fauna on the Pacific slope, which represents the Mesoamerican dry forest fauna. – 2) The highland fauna, a distinct group of species that occur in Costa Rica and Chiriqui, Panama highlands. – 3) The wet forest fauna of the Caribbean slope. It is derived primarily from South American groups where as the highland and Guanacaste fauna are a mixture of North and South American groups. Life Zone Distribution With a steep dry season gradient of increasing moisture from Pacific to Caribbean slope, create remarkably distinct vegetation in the different life zones. – This also causes Avian species diversity to vary across the different life zones. Life Zones Continued Zone 4 (Lower Montane rain Zones 5 and 6 (Pre-montane forest) rain and tropical wet forests) – Has Highest proportion of – On Caribbean slope (315 to unique species (9%). 278 species, relatively) – Lowest species richness off all – Most species rich life zone life zones (121 regularly – These middle-elevation zones occurring species). have highest species diversity This is due to its small of any site in Costa Rica geographic extent and isolation from the more – They are low enough in diverse higher elevation elevation to include the upper faunas. limit of the ranges of many lowland species as seasonal migrants. Zone 6 includes a lake of 2- ha that attracts water birds not seen elsewhere in Montverde. The Importance of the Corridor The Corridor is the space between the Cloud Forest and Rain-Shadow Forest. The Monteverde Corridor is an ecological connection between the highlands and the lowlands. Corridors are critical for area-sensitive species which require large, interconnected areas to maintain viable populations. Corridors will interconnect various plant, and animal habitats. Species Accumulation Curve Zone 6 on the Caribbean slope site is much more diverse than that of the Pacific slope and after several hundred captures, there is no indication of the level of species richness at which the curve will flatten out. – Most research takes place on the Pacific slope where species richness is intermediate. The rate of accumulation of species is plotted as a function of the number of mist-net captures. – Canopy species are under represented Differences between Pacific and Caribbean slopes Elevational migration is much less pronounced on the Pacific slope, breeding species tend to remain resident year round on their territories. – Ecological differences are between dry forests and the moist highland forests of the Caribbean side: may hinder migration. – Problem: Deforestation is more pronounced on Pacific slope where there tends to be more seasonal migration between adjacent dry and gallery forests. Restriction of Species to one life zone The pattern of species occurring only in specific life zones is remarkable because habitat specialization occurs on a very small spatial scale. Most species of birds can only be found in one of the six principle life zones. – As one walks from the Pacific slope to the Caribbean slope a series of distinct bird communities is found. – This causes a high alpha species diversity (many species in one habitat) and a high beta species diversity (a high turnover of species across adjacent habitats. Migration Bird populace consists of permanent residents, seasonal migrants, and elevational migrants. – Long distance migrants either breed in North or Central America during the summer and migrate down to Costa Rica during the non- breeding season. – Elevational Migrants breed at one elevation during the non-breeding season and migrate to other slopes during non-breeding season. Migration Types Long Distance Migration: Elevational Migration: – 91 species or 21% are long- – Ex: the Resplendent Quetzals. distance migrants. – The broad pattern is a four – Some such as the Swallow- stage annual movement. tailed Kite or the Yellow-Green 1) Courtship and nesting Vireo breed in Montverde and occur in cloud forest habitats migrate to South America in between January and June. non-breeding season. 2) After nesting, adults and – They decrease in number with off-spring move to lower elevations on Pacific slope. increase in elevation, occurring most commonly in Four months later birds move back to higher elevations Zones 1-2 and 5-6. used for nesting. – Relatively low competition They then move across the between resident and migrant continental divide to the birds. Caribbean slope until nesting season approaches. Why Migrate? The pattern is to believed too be the result of the availability of food sources such as the family of Lauraceae. Monteverde Corridor for Endangered Species Distinct Species in Each Reserve Due to amount of moisture and altitude, the species are distinctly different in each type of forest. Cloud Forest has 160 tree species. Rain-Shadow Forest has 132 tree species. Only ten of these tree species can be found in both areas. 21 bird species in Rain-Shadow Forest never live in the Cloud Forest. Lauraceae Tropical Trees Part of Avocado Family. Primary source of food for birds and mammals. Rain-Shadow has 17 species. Cloud Forest has 13 species. – Not one species can be found in both areas. Problems Not much rain-shadow forest is left. – Due to cattle raising & coffee growing, large Costa Rican industries. • Also because when birds migrate lower, they crowd into the remaining forest and eat anything that has not been eaten. • So little of what is left is protected. • An estimated 2,000 acres is needed to be protected to be sure of the rain-shadow forests survival. • Currently only 650 acres are protected. Three Important Ecological Functions 1. Corridor is critical habitat for fruit-eating birds. 2. Corridor will Protect Endangered Rain- Shadow Forests. 3. Corridor provides critical biological area for the region.
Pages to are hidden for
"brian"Please download to view full document