Andean Forests Research Articles

Little trace of floristic homogenization in peri‐urban Andean secondary forests despite high anthropogenic transformation

Abstract Pervasive human impact in heavily transformed landscapes may lead disturbance‐adapted species to thrive, resulting in floristic homogenization across forest stands. However, environmental heterogeneity and dispersal limitation may be antagonistic forces to homogenization, maintaining inherent floristic differentiation across sites. We evaluated the extent to which peri‐urban Andean forests are undergoing floristic homogenization in both late‐ and early‐successional stands. We considered seedling assemblages as well, as they provide key insights into forests’ future. We then quantified the relative importance of dispersal limitation and environmental filtering in determining the observed patterns of floristic similarity across the landscape. We used tree, seedling, soil and climatic data from six sites located in the high plain where Bogotá lies (Colombia). Within each site, we established six 20 × 20 m plots, three in early‐successional stands and three in late‐successional stands, for a total of 36 plots. To evaluate the extent of floristic homogenization, we defined tree floristic similarity among late‐successional stands as a baseline, reflecting our best‐guess of the original species composition that would have once occurred previous to intense anthropogenic intervention. Tree floristic turnover across the landscape was alike in late‐ and in early‐secondary stands, a finding that does not support the homogenization scenario. Seedling species composition, in contrast, was more homogeneous among early‐ than among late‐secondary stands, an outcome suggestive of homogenization. The relative importance of spatial and environmental drivers shifted between life stages. Distance between plots was the best predictor of tree species dissimilarity (29% of variance explained), whereas seedling compositional variation was more sensitive to changes in environmental conditions (41% of the variance explained). Relative humidity and several variables related to soil fertility showed a significant effect on floristic dissimilarity across the landscape, although significant factors were often different between life stages. Synthesis. Despite high anthropogenic transformation, we found little trace of floristic homogenization in these peri‐urban landscapes. Inherent floristic differentiation, promoted both by dispersal limitation and environmental heterogeneity, suggests that all patches are important to the conservation in these Andean forests, critical centres of endemism.

Studies on raspy crickets: New Triaenogryllacris species (Orthoptera: Gryllacrididae).

The genus Triaenogryllacris is redescribed and a key for identification of the species is provided. When dealing with observations of iNaturalist, accurate data about the distribution of T. triaena (the type species) are obtained, and three color forms are indicated: yellow, pink and green. Two new species are described here: T. diaena n. sp. and T. horaciotrianai n. sp., expanding the expected geographic distribution for the genus, thus recorded, from the Andean forests of Ecuador and Colombia's three mountain ranges. Finally, the characters and distribution of Triaenogryllacris are discussed, contrasting with the other taxa described for the family Gryllacrididae.

Evaluating the Impacts of a Small-Grants Program on Sustainable Development and Biodiversity Conservation in Andean Forest Landscapes

International sustainable development and conservation agendas can help regional decision makers to frame their own agendas. Agendas can guide programs and initiatives that drive funding and capacity development for research, and the research, in turn, provides knowledge, evidence, capacity building, and impetus for action. Deficits in research capacity, knowledge, and funding confound efforts on the impact pathway from agenda to outcome. Small-grants programs can play an important role in filling these gaps. In this paper, we evaluate a suite of impacts of a small-grants program linked to a regional research agenda for the Andean forest landscape. Using the concept of additionality, and analyzing the database of applications for the solicitation process and responses to a questionnaire by awardees, we evaluated the effects of the funding on research input, outputs and outcomes, and transformative application to sustainable development. We found that the solicitation process, which yielded 180 applications, fell short of its goal of attracting applicants well distributed among the Andean countries, applications from women, and applications for interdisciplinary transformative research projects. Nevertheless, the 15 projects that were funded did ultimately cross disciplinary lines, result in diverse outputs and outcomes, and help to advance work toward achieving sustainable development and biodiversity conservation in the Andean forest landscape. We recommend that small-grants programs that focus narrowly on a topic or region be supported and that they strive to elevate regional researchers and women in the community of practice.

<strong><em>Burmeistera andakiana</em> and <em>B. boyacensis</em> (Campanulaceae, Lobelioideae), two new species from the Eastern Cordillera of Colombia</strong>

Burmeistera andakiana and B. boyacensis are described as new species primarily from the Eastern Cordillera of Colombia. The first species, closely related to B. brachyandra and B. ramosa, grows in sub-Andean forests at the eastern slopes of the Cordillera in the departments of Caquetá and Putumayo, with a few lowland populations, being the only Colombian species of the genus that reaches Amazonian forests. The second species, closely related to B. orientalis, has been collected at edges of Andean forests in both flanks of the Eastern Cordillera in the department of Boyacá. The new species are illustrated and their relationships are discussed. Both species differ from their relatives by a number of vegetative and reproductive traits related to the indumentum of the stem, the architecture and size of leaves, the morphology and indumentum of floral organs, and the shape of the fruits. We suggest that both species be considered as critically endangered.

Toxoplasma gondii infection in Colombia with a review of hosts and their ecogeographic distribution.

Toxoplasma gondii is one of the most prevalent zoonotic protozoan parasites among warm-blooded animal populations (humans included) around the world, causing multiple clinic manifestations including death in the most severe cases of infection. Due to the versatile life cycle of T. gondii and its diversity of potential hosts, there is a common perception that natural areas and wildlife are highly prevalent reservoirs for the parasite; however, information and reports of the parasite on wildlife populations in Colombia are scarce. Using PRC-based detection analyses of the B1 gene, we evaluated the presence of T. gondii in 49 native small mammal species (10% of the mammal species of Colombia) from 4 different undisturbed natural habitats. Additionally, to understand the ecogeographical distribution of the parasite in Colombia, we developed a literature search of infection reports including information on the host species, density of records and occurrence patterns (using landcover and ecoregions) in natural, rural and urban areas. Our literature review showed a total of 8,103 reports of T. gondii for Colombia of which 86% were related to humans, and 14% to non-human mammals and other categories, with just a single report associated to wildlife; additionally, 82% of all reports were associated to urban areas whereas only 18% to rural sites. Based on the negative results for the presence of T. gondii in our PCR-based analyses and our literature search, we suggest that T. gondii has a synanthropic distribution in Colombia occurring in ecoregions as variable as the xeric scrubs in the northern lowlands and humid montane Andean forests, also we show a lack of information on the parasite relationship with wildlife, a concerning fact given that zoonoses are the leading mechanism for the emergence of infectious diseases.

Assessment of the rarity and conservation status of the Colombian endemic brown hairy dwarf porcupine Coendou vestitus

AbstractThe brown hairy dwarf porcupine Coendou vestitus is a poorly studied Andean species endemic to Colombia. Its current Red List category is contradictory: globally it is categorized as Data Deficient but in Colombia it is categorized as Vulnerable. This contradiction has limited the implementation of conservation programmes. We evaluate the level of rarity of the species and provide consolidated information for a new assessment of its Red List status. We reviewed literature, photographs, and voucher specimens in natural history collections. Using the confirmed records, we estimated the extent of occurrence (EOO) based on the minimum convex polygon and the area of occupancy (AOO) summing the area of grid squares occupied by the species. We found that C. vestitus is very rare, with a small range, low estimated population density, occurrence in only one habitat type and small body size. The species has an EOO of 3,323 km2 and an AOO of 24 km2, based on six confirmed localities, all on the western slopes of the Eastern Cordillera, in the central Andean region of Colombia. Based on the species' rarity, restricted distribution, and threats to its natural habitat, we recommend its categorization as Endangered on the IUCN Red List. This will help delineate research and conservation efforts for this porcupine, which has a highly restricted range and inhabits the threatened Andean forest.

A new genus of oryzomyine rodents (Cricetidae, Sigmodontinae) with three new species from montane cloud forests, western Andean cordillera of Colombia and Ecuador.

The Andean cloud forests of western Colombia and Ecuador are home to several endemic mammals; members of the Oryzomyini, the largest Sigmodontinae tribe, are extensively represented in the region. However, our knowledge about this diversity is still incomplete, as evidenced by several new taxa that have been described in recent years. Extensive field work in two protected areas enclosing remnants of Chocó montane forest recovered a high diversity of small mammals. Among them, a medium-sized oryzomyine is here described as a new genus having at least three new species, two of them are named and diagnosed. Although externally similar to members of the genera Nephelomys and Tanyuromys, the new genus has a unique molar pattern within the tribe, being characterized by a noticeable degree of hypsodonty, simplification, lamination, and third molar compression. A phylogeny based on a combination of molecular markers, including nuclear and mitochondrial genes, and morphological data recovered the new genus as sister to Mindomys, and sequentially to Nephelomys. The new genus seems to be another example of a sigmodontine rodent unique to the Chocó biogeographic region. Its type species inhabits cloud forest between 1,600 and 2,300 m in northernmost Ecuador (Carchi Province); a second species is restricted to lower montane forest, 1,200 m, in northern Ecuador (Imbabura Province); a third putative species, here highlighted exclusively by molecular evidence from one immature specimen, is recorded in the montane forest of Reserva Otonga, northern Ecuador (Cotopaxi Province). Finally, the new genus is also recorded in southernmost Colombia (Nariño Department), probably represented there also by a new species. These species are spatially separated by deep river canyons through Andean forests, resulting in marked environmental discontinuities. Unfortunately, Colombian and Ecuadorian Pacific cloud forests are under rapid anthropic transformation. Although the populations of the type species are moderately abundant and occur in protected areas, the other two persist in threatened forest fragments.

Four new Neotropical species of Eudicrana Loew (Diptera, Mycetophilidae, Sciophilinae) from the Colombian high Andean ecosystems, with comments on the genus.

Four new species of the sciophiline genus Eudicrana Loew are described for the Eastern and Central Andes of Colombia–Eudicrana silvaandinasp. nov., E. chingazasp. nov., E. maculatasp. nov. and E. merizaldei. These are the first species of Eudicrana described from the extreme northern range of the Andes. The altitudinal distribution of these species in the paramos and high Andean forest ecosystems is restricted to 1750–3660 m a.s.l. and some other information on the environment is briefly discussed. A key for the Colombian species of Eudicrana is provided and a discussion is elaborated on the position of these species within the genus.

Germinación de semillas de Quercus humboldtii Bonpl. (Fagaceae): especie vulnerable del bosque Altoandino

El roble colombiano (Quercus humboldtii) es una especie endémica, dominante y vulnerable de los bosques altoandinos. Su madera y fruto se han utilizado tradicionalmente en pequeña escala por las poblaciones rurales. Una mayor sincronía del proceso de germinación podría facilitar la producción de plántulas para su uso en los programas de conservación. En vivero, se evaluó la emergencia mediante la inmersión de semillas en cuatro soluciones de ácido giberélico (GA3) por 24 horas (0, 150, 300 y 600 mg L-1), a 4 °C. Se adoptó un diseño completamente al azar con cuatro repeticiones de 25 semillas. El tiempo medio de emergencia tuvo una media de 32 días; sin diferencias estadísticamente significativas entre las diferentes dosis. No hubo efecto del GA3 para la emergencia de plántulas hasta 300 mg L-1 (media= 92 %); sin embargo, fue desfavorable con 600 mg L-1 (20 %). Las semillas frescas de roble andino poseen un alto contenido de humedad (38 %). Lo anterior revela un probable comportamiento recalcitrante. Este estudio confirma, como en la mayoría de los encinos blancos del trópico, la ausencia de latencia y la alta viabilidad de sus semillas. El uso del GA3 no es un tratamiento pregerminativo útil para acelerar y uniformizar la emergencia de plántulas de Q. humboldtii.

Reduced tree density and basal area in Andean forests are associated with bamboo dominance

Forest structure and composition play an essential role in determining the carbon storage capacity of tropical forests. Andean forests, with great potential for carbon accumulation, include large expanses of high-density woody bamboo communities. Woody bamboos can potentially alter forest structure, composition and dynamics and thus can affect carbon storage capacity; however, they are commonly excluded from forest monitoring and modelling. With the aim of documenting patterns of bamboo abundance and disentangling its association with forest structure, we carried out a bamboo census in seven 1-ha long-term forest monitoring plots situated across a large elevation gradient (1000–3600 m a.s.l.) in the Peruvian Andes. We determined that bamboo is a dominant plant group in the study area. In every plot, bamboos were the most common genera in terms of number of stems, and in two of the plots bamboo species were among those with the greatest basal area. We used a combination of Generalized linear mixed models (GLMM) and structural equation modelling (SEM) to hypothesize a causal framework and determine the direction and size of the effects of bamboo abundance (basal area) on number of individual trees, total tree basal area, mean tree basal area, mean tree growth rate and tree mortality rate. We found an overall negative association between bamboo abundance and total tree basal area driven mainly by reduced tree density (directly and indirectly mediated by an increase in tree mortality). However, the decrease in tree density and the increase in tree mortality are also associated with a small increase in tree diameter (mean tree basal area). Overall, the negative association between bamboo abundance and tree basal area suggests a lower biomass accumulation and thus a lower carbon storage capacity of trees in Andean forests where bamboo is dominant. Our results, which show the importance of bamboo in determining forest function, highlight the need for including bamboo in monitoring efforts and modeling studies.

The legacy of biogeographic history on the composition and structure of Andean forests.

The biogeographic origin of species may help to explain differences in average tree height and aboveground biomass (AGB) of tropical mountain forests. After the Andean uplift, small-statured trees should have been among the initial colonizers of the highlands (new cold environment) from the lowland tropics, since these species are pre-adapted to cold conditions with narrow vessels that are relatively resistant to freezing. If the descendants of these small-statured clades continue to dominate tropical highland forests, there will be a high co-occurrence of close relatives at high elevations. In other words, this scenario predicts a systematic decline in tree size, AGB, and phylogenetic diversity with elevation. In contrast, the colonization of Andean forests by some large-statured clades that originated in temperate regions may modify this expectation and promote a mixing of tropical and temperate clades, thereby increasing the phylogenetic diversity in tropical highland forests. This latter scenario predicts an increase or no change of tree size, AGB, and phylogenetic diversity with elevation. We assessed how the historical immigration of large-statured temperate-affiliated tree lineages adapted to cold conditions may have influenced the composition and structure of Andean forests. Specifically, we used 92 0.25-ha forest inventory plots distributed in the tropical Andes Mountains of Colombia to assess the relationship between the phylogenetic diversity and AGB along elevational gradients. We classified tree species as being either "tropical affiliated" or "temperate affiliated" and estimated their independent contribution to forest AGB. We used structural equation modeling to separate the direct and indirect effect of elevation on AGB. We found a hump-shaped relationship of phylogenetic diversity, AGB, and tree size with elevation. The high phylogenetic diversity found between 1,800-2,200m above sea level (asl) was due to the mixing of highland floras containing many temperate-affiliated species, and lowland floras containing mostly tropical-affiliated species. The high AGB in highland forests, which contrasted with the expected decline of AGB with elevation, was likely due to the significant contribution of temperate-affiliated species. Our findings highlight the lasting importance of biogeographic history on the composition and structure of Andean mountain forests.

Tritrophic web structure in montane Andean forests undergoing ecological restoration

Parasitism represents an important ecosystem service, reducing pest abundance. Since most hosts of parasitoids are herbivores, plant diversity likely shapes both herbivore and parasitoid assemblages. While restoration efforts are being adopted worldwide, mitigating habitat degradation, little is known about how tritrophic webs are organized among plant species in recovering ecosystems. Here we collected exposed herbivores (Coleoptera and Lepidoptera larvae) during four sampling months from five plant species in two restoration areas in Andean forests in southern Ecuador. Larvae were kept in the laboratory until the emergence of the adults or parasitoids. Herbivore and parasitoid diversity and parasitism rates were compared among plants. A total of 82 immature individuals (56 Lepidoptera and 26 Coleoptera—23 predatory and 3 herbivorous) were collected and 102 parasitoids emerged (all Hymenoptera except one tachinid fly). Herbivore and parasitoid assemblages showed a high species turnover between plant species. The mean parasitism rate was 35.14% and 46.67% in the two restoration sites, respectively, with no significant differences found within forests or plants. Long-term food web monitoring should be carried out to improve our understanding of how ecosystems under ecological restoration programs functionally recover.

Interception and runoff of the high Andean forest in the “El Malmo” Protective Forest Reserve

Tropical forests are globally important for their biodiversity and the ecosystem services, and they are key to the global water cycle. Anthropogenic changes and pressures affecting tropical forests affect the fundamental role of tropical forests in water supply. This study evaluates the relationship between the vegetation coverage in the high Andean forest of the “El Malmo” Protected Forest Reserve and the quality and quantity of intercepted runoff; the life zone analyzed comprises four types of cover: dense high Andean forest, low secondary vegetation, broadleaf plantation and mosaic of pasture with natural spaces. Eight setups (two per cover) were installed, each composed of a runoff plot and a precipitation meter under the canopy; data collection was carried out every eight days for 24 weeks. The results indicate that precipitation interception does not vary in each canopy, while surface runoff and its quality with respect to sediment are affected, which is mainly due to differences in soil physical conditions. The cover that allows the best dimensions of water quality and quantity is the dense high Andean forest. The influence of anthropic intervention in the area and the presence of invasive species negatively affect these variables. This work provides knowledge on the hydrological behavior of the reserve for forest management. It also generates information on the interception/runoff relationship in the forests of the Cundiboyacense region, which has not been available until now, becoming an starting point of comparison for further research in high Andean ecosystems.

Rasgos funcionales de la madera de tres bosques en Colombia: Bosque Seco, Andino y Alto-Andino

This research analyzed twelve (12) wood functional traits in 144 species of three forests in Colombia. The traits were classified according to their incidence in the functions of storage, support and conduction in the xylem. The conduction relations in the three forests suggest that when the pores diameter is big, its density decrease, and at the same time the pits diameter increase, as a strategy to guarantee exchange between vessels. The tracheid length is related to the fibers length and the pores diameter, because the tracheids fulfill both functions: conduction and support. Tracheids are only in the Andean and High Andean Forest species. The species of the High Andean Forest have long and wide rays allowing greater storage capacity and horizontal conduction. In the Andean Forest species, the fibers length and tracheids length were higher. The Dry forest species had the highest wood densities, however, the values of fiber length and thickness fiber were the lowest, reducing their support capacity. Six functional plant types (TFPs) are established and described from the evaluated traits.

Nest and egg description of the Andean Guan (Penelope montagnii, Cracidae)

Chachalacas, guans, and curassows are the most threatened Neotropical birds. However, information about their reproduction has not been well-documented for several species. Here, we provide the first description of nest and eggs of the Andean Guan (Penelope montagnii) in Andean highland forests from Colombia. We also compile nest and egg characteristics in the other 14 Penelope species. An active nest made of dry leaves and ferns was found over a simple platform 1.22 m above the ground on a Daphnopsis caracasana tree. Like other Penelope species, clutch size consisted of three oval and white eggs. The average egg measurements and mass were as follows: 69.66 mm × 46.32 mm, 81.6 g. We gathered the available information on the nest type, nesting materials, phorophyte, nest dimensions, the distance of the nest to the ground, and the clutch size and egg dimensions for all Penelope species. We only found three species with detailed information of eggs and nests, besides the Andean Guan reported here. In general, these species construct their nests over simple platforms, employing plant materials available from the environment. Nests present dimensions with external and internal diameters between 30–60 cm and 18–38.5 cm respectively, and depths ranging from 5 to 25 cm. Importantly, these trends are far to be conclusive due to the remarkable gaps of knowledge in nesting ecology for most of Penelope species. We encourage additional studies on reproductive ecology for these birds.

Plantas amenazadas de la colección viva del Jardín Botánico de Bogotá


 
 
 
 
 
 
 
 En el manuscrito se encuentra el listado de plantas amenazadas presentes en el Jardín Botánico de Bogotá (JBB) inventariadas desde el año 2017 con datos taxonómicos, fisonómicos, y fitosanitarios, entre otros. Debido al continuo enriquecimiento de sus colecciones, el listado de plantas se ha actualizado y se han georreferenciado todos sus individuos. Se registran 89 especies de plantas correspondientes a 19 familias y 37 géneros en las siguientes categorías de conservación a nivel nacional: en peligro (34), en peligro crítico (14) y vulnerable (39). La familia con mayor número de especies amenazadas es Orchidaceae. Quercus humboldtii, Ceroxylon quindiuense y Masdevallia ignea son las especies amenazadas con mayor número de individuos en el JBB. De acuerdo con su distribución, los individuos de este grupo de plantas tienen mayor densidad en la colección de Bosque Andino con énfasis en magnolias, y en áreas de trabajo como el invernadero de bromelias y orquídeas de clima frío. Es importante orientar esfuerzos en la propagación de alrededor de 62 especies que tienen menos de diez individuos, así como su enriquecimiento con material de campo si las condiciones poblacionales de sitios reportados en la región lo permiten. El Jardín Botánico de Bogotá contribuye en la conservación de plantas andinas y altoandinas, y otras zonas de Colombia, al mantener este grupo de la flora amenazada. Los resultados expuestos en el presente documento son insumo para la toma de decisiones por parte de la administración del Jardín Botánico para el manejo, el mantenimiento, el enriquecimiento y el conocimiento de sus colecciones botánicas.
 
 
 
 
 
 
 

Discoveries in indigenous territories: Two new species of Lepanthes (Orchidaceae: Pleurothallidinae) in southwestern Colombia

Two new species of Lepanthes from the Central Cordillera of the Colombian Andes are described and illustrated. Both were found during a botanical expedition to Puracé National Natural Park, within the high Andean forests ecosystem of the municipality of Puracé, in the department of Cauca.
 Key Words: Cauca, Colombian Massif, Kokonukos, Paletará, Puracé National Natural Park

Multiproxy analysis of a Lateglacial-Holocene sedimentary section in the Fuegian steppe (northern Tierra del Fuego, Argentina): Implications for coastal landscape evolution in relation to climatic variability and sea-level fluctuations

We report the sedimentology, palynology, geochemistry, and diatom assemblages of a well-dated succession at Laguna Las Vueltas (LV) on the Atlantic coast of the Fuegian steppe in southern Argentina. The multiproxy analysis offers a unique opportunity to study the evolution of this coastal landscape in relation to past sea level and climate changes in the southern high latitudes. After ca. 19,000 cal yr BP, the sediments were subjected to subaerial exposure and oxidation linked to a low sea level. The Sr/Ba ratio (a paleosalinity geochemical parameter) indicates variations in the water body level, and diatoms imply the existence of an ephemeral and brackish-freshwater body subject to desiccation under arid conditions. Between ca. 11,600 and 8500 cal yr BP, a shrubby steppe vegetation, mainly composed of Asteraceae subf. Asteroideae, spread over the coastal area associated with a shallow freshwater body and the deposition of fine-grained sediments in low-energy environments, all indicative of low effective moisture and warm climate conditions. Between ca. 8500 and 8100 cal yr BP, salt carpet vegetation, dominated by Chenopodiaceae, developed around a coastal lagoon in response to the Holocene marine transgression. The record of dinocysts and geochemical data indicate marine influence at this time. Between ca. 8100 and 7000 cal yr BP, salt marshes colonized the coastal area. A coastal lagoon with a more restricted connection to the sea and minor freshwater input are inferred, linked to the beginning of a regressive phase. After ca. 7000 cal yr BP, grassland vegetation and an open shrub stratum developed along with a shallow lake (pan) that was disconnected from the sea, following a fall in the sea level and regression. Fluctuations in the water level of the pan and changes in the physical-chemical conditions, as indicated by fluctuations in Mn/Fe, Ti/Ca, Rb/Sr, Ca, TIC and TOC, suggest abrupt events of desiccation and flooding. Between ca. 4500 and 2000 cal yr BP a drier phase is indicated by changes in vegetation, algal content and geochemistry of the pan. A grassland vegetation and a shallow lake with seasonal water level variations characterized the last 2000 years. Our results from LLV area match well with Andean forest fluctuations and regional climatic conditions recorded from Tierra del Fuego and Chilean southwest.

Widely distributed breeding populations of Canada warbler (Cardellina canadensis) converge on migration through Central America

BackgroundTo effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered. Most research on Nearctic-Neotropical migratory birds has focused on the breeding grounds resulting in a general lack of knowledge regarding the wintering and migratory periods. The Canada Warbler (Cardellina canadensis) has declined by 71% from 1970 to 2012, at a rate of 2.9% per year, and is listed as Threatened in Canada. As with most Nearctic-Neotropical migrants, conservation efforts outside the breeding range are limited by a poor understanding of migration routes and the connectivity between specific breeding and wintering populations.ResultsTo determine migratory routes of multiple breeding populations of Canada Warblers, we directly-tracked individuals using light-level geolocators deployed at four sites across the breeding range, spanning approximately 43 degrees in longitude (Alberta, Manitoba and Québec, Canada, and New Hampshire, USA). Twenty-five geolocators with usable data were recovered from three sites and were analyzed using FlightR to determine fall migration routes (n = 18) and individual wintering sites (n = 25). Individuals from all breeding populations took a western fall migration route at the Gulf of Mexico; with 77.8% of birds funnelling into a narrow geographic space along the western side of the Gulf of Mexico (97°W-99°W). We found no evidence for population-specific, parallel migration routes. Most individuals (72%) overwintered in Colombia. The remaining individuals overwintered in Venezuela.ConclusionsOur results demonstrate convergence of migratory routes around a migration barrier for individuals originating from widely distributed breeding areas. Further, we suggest the potential importance of habitat around the Gulf of Mexico during migration and Andean forest in Colombia as overwintering habitat for this threatened species. Future research should be directed at understanding how these areas are used by Canada Warblers.

Reconstructing Long Term High Andean Forest Dynamics Using Historical Aerial Imagery: A Case Study in Colombia

High Andean forests are biodiversity hotspots that also play key roles in the provisioning of vital ecosystem services for neighboring cities. In past centuries, the hinterland of Andean fast-growing cities often experienced a dramatic decline in forested areas, but there are reports that forest cover has been recovering recently. We analyzed aerial imagery spanning the years 1940 to 2007 from nine administrative localities in the Eastern Andean Cordillera of Colombia in order to elucidate precise patterns of forest vegetation change. To this aim, we performed image object-based classification by means of texture analysis and image segmentation. We then derived connectivity metrics to investigate whether forest cover trajectories showed an increase or decrease in fragmentation and landscape degradation. We observed a forest cover recovery in all the examined localities, except one. In general, forest recovery was accompanied by an increase in core habitat areas. The time scale of the positive trends identified partially coincides with the creation of protected areas in the region, which very likely furthered the recovery of forest patches. This study unveils the long-term dynamics of peri-urban high Andean forest cover, providing valuable information on historical vegetation changes in a highly dynamic landscape.