Review: Vega, Ayala, Morrone, Organista (2000) Track Analysis and conservation priorities in the cloud forests of Hidalgo, Mexico. Diversity, 6(3):137-143.

Feature Paper: DOWNLOAD Vega, Ayala, Morrone, Organista (2000) Track Analysis and conservation priorities in the cloud forests of Hidalgo, Mexico. Diversity, 6(3):137-143.

Author Abstract: A track analysis based on the distributional patterns of 967 species of vascular plant taxa (gymnosperms, angiosperms and pteridophytes) was performed to assess conservation priorities for cloud forests in the state of Hidalgo, Mexico, ranged in the municipalities of Chapulhuacán, Eloxochitlán, Molocotlán, Pisaflores, Tenango de Doria, Tlahuelompa and Tlanchinol, as well as five floristically equivalent areas in the states of Veracruz (Teocelo and Helechales), Tamaulipas (Gómez Faríias), Morelos-México (Ocuilan) and Oaxaca (Huautla de Jiménez). In order to detect generalized tracks we employed a new parsimony method, where clades (considered equivalent to generalized tracks) are defined forbidding homoplasy and acting like a compatibility algorithm. Several generalized tracks were found connecting these areas. Cloud forests of Chapulhuacán were connected according to three different generalized tracks and thus have a higher value, qualifying as a priority area of the conservation of cloud forests in the state of Hidalgo.

Note to Readers: Follow links above for author email, full article text, or the publishing scientific journal. Author notes in my review are in quotes.

Review: We'll finish up the week by examining how track analyses can be interpreted to determine areas to focus conservation efforts.

The authors restricted their analysis to a single ecosystem (cloud forests) over five states (Hidalgo, Veracruz, Tamaulipas, Morelos-México, and Oaxaca) in Mexico. Cloud forests were chosen because conservation has been difficult. They are a naturally fragmented ecosystem, often separated by lowlands between mountains (they require elevations of 600 to 3000 meters). As individual forests within a larger area are destroyed through "deforestation and agricultural exploitation," conservationists are tasked with determining which forest areas (often with different and unique floras) should be prioritized for conservation.

The authors first identified all the vascular plants within cloud forests surrounding Hidalgo, Mexico (specifics above). Presence-Absence data were constructed for the 967 species of plants identified for all cloud forests. Instead of taking a normal panbiogeographic approach for identifying "generalized tracks" (remember to look at Week 3's review of panbiogeography for all terms), the authors proposed a new analysis based on cladistic parsimony. Cladograms were generated for all taxa and then converted to generalized tracks "by joining together their minimal geographical distance [to] the areas included in the same clade." In other words, the authors used cladistics to determine clustering and relatedness of taxonomic compositions within each cloud forest locality in the study, then used those cladistic clusters to create generalized tracks rather than relying on minimal spanning tree algorithms from a purely geographical perspective.

The authors continued their analysis in a stepwise fashion, whereby they first used all species presence and absence data to determine an original cladogram, then determined which species in the matrix "defined" the outcome of the cladogram (the species comprising the basal branches of the cladogram). Those species records were then removed from subsequent analyses to determine secondary cladograms, and so forth until only isolated localities remained.

The authors converted each cladogram into generalized tracks as described above, and by "comparing the different generalized tracks obtained, we found that Chapulhuacán is a panbiogeographic node according to three different connections between generalized tracks; and Huautla de Jiménez, Gómez Farías, Eloxochitlán and Pisaflores are panbiogeographic nodes according to one connection between generalized tracks. For this reason, Chapulhuacán turned out to be the most important area for conservation because it has different biotic affinities, so it should have the first priority when protecting the cloud forests of Hidalgo."

The authors were faced with a situation where there is a fragmented community of ecosystems, with each isolate containing a fairly unique composition of species and where many endemic plants existed for each area, coupled with no protection for any of the forests in the study. Rather than conserving all cloud forests (the ideal but impractical situation), the authors used science to determine the area with "species dorm different ancestral biotas" that represented the greatest uniqueness of all isolated cloud forests in a region.

The authors' approach differs from typical conservation approaches that only look at total species richness. The authors note that "instead of the species-richness criterion, which considers that all species are equivalent, track methods measure the distinctiveness among biotas, weighting those areas with representatives of different ancestral biotas. The track approach allows conservationists to integrate distributional data efficiently, which could be a complement to… other analyses, e.g. phylogenetic indices or complementarity."

The authors conclude with the take-home message that "the biodiversity crisis is far from being a simple matter, and different approaches should be applied and tested in order to allow its appropriate conservation" and that the general public should be educated in better understanding "the interrelationship between biology, geology, history and conservation."

Next we'll review two papers, one tying in with today's review by focusing on conservation, and the other examining the biogeography of the Pacific ocean (and island floras and faunas) based on multiple biogeographic schemes and approaches.