German Forero-Medina

Elevational ranges of birds on a tropical montane gradient lag behind warming temperatures.

Background Species may respond to a warming climate by moving to higher latitudes or elevations. Shifts in geographic ranges are common responses in temperate regions. For the tropics, latitudinal temperature gradients are shallow; the only escape for species may be to move to higher elevations. There are few data to suggest that they do. Yet, the greatest loss of species from climate disruption may be for tropical montane species. Methodology/Principal Findings We repeat a historical transect in Peru and find an average upward shift of 49 m for 55 bird species over a 41 year interval. This shift is significantly upward, but also significantly smaller than the 152 m one expects from warming in the region. To estimate the expected shift in elevation we first determined the magnitude of warming in the locality from historical data. Then we used the temperature lapse rate to infer the required shift in altitude to compensate for warming. The range shifts in elevation were similar across different trophic guilds. Conclusions Endothermy may provide birds with some flexibility to temperature changes and allow them to move less than expected. Instead of being directly dependent on temperature, birds may be responding to gradual changes in the nature of the habitat or availability of food resources, and presence of competitors. If so, this has important implications for estimates of mountaintop extinctions from climate change.

Movement behaviour within and beyond perceptual ranges in three small mammals: effects of matrix type and body mass.

1. For animal species inhabiting heterogeneous landscapes, the tortuosity of the dispersal path is a key determinant of the success in locating habitat patches. Path tortuosity within and beyond perceptual range must differ, and may be differently affected by intrinsic attributes of individuals and extrinsic environmental factors. Understanding how these factors interact to determine path tortuosity allows more accurate inference of successful movements between habitat patches. 2. We experimentally determined the effects of intrinsic (body mass and species identity) and extrinsic factors (distance to nearest forest fragment and matrix type) on the tortuosity of movements of three forest-dwelling didelphid marsupials, in a fragmented landscape of the Atlantic Forest, Brazil. 3. A total of 202 individuals were captured in forest fragments and released in three unsuitable matrix types (mowed pasture, abandoned pasture and manioc plantation), carrying spool-and-line devices. 4. Twenty-four models were formulated representing a priori hypotheses of major determinants of path tortuosity, grouped in three scenarios (only intrinsic factors, only extrinsic factors and models with combinations of both), and compared using a model selection approach. Models were tested separately for individuals released within the perceptual range of the species, and for individuals released beyond the perceptual range. 5. Matrix type strongly affected path tortuosity, with more obstructed matrix types hampering displacement of animals. Body mass was more important than species identity to determine path tortuosity, with larger animals moving more linearly. Increased distance to the fragment resulted in more tortuous paths, but actually reflects a threshold in perceptual range: linear paths within perceptual range, tortuous paths beyond. 6. The variables tested explained successfully path tortuosity, but only for animals released within the perceptual range. Other factors, such as wind intensity and direction of plantation rows, may be more important for individuals beyond their perceptual range. 7. Simplistic scenarios considering only intrinsic or extrinsic factors are inadequate to predict path tortuosity, and to infer dispersal success in heterogeneous landscapes. Perceptual range represents a fundamental threshold where the effects of matrix type, body mass and individual behaviour change drastically.

Representation of Global and National Conservation Priorities by Colombia's Protected Area Network

Background How do national-level actions overlap with global priorities for conservation? Answering this question is especially important in countries with high and unique biological diversity like Colombia. Global biodiversity schemes provide conservation guidance at a large scale, while national governments gazette land for protection based on a combination of criteria at regional or local scales. Information on how a protected area network represents global and national conservation priorities is crucial for finding gaps in coverage and for future expansion of the system. Methodology/Principal Findings We evaluated the agreement of Colombias protected area network with global conservation priorities, and the extent to which the network reflects the countrys biomes, species richness, and common environmental and physical conditions. We used this information to identify priority biomes for conservation. We find the dominant strategy in Colombia has been a proactive one, allocating the highest proportion of protected land on intact, difficult to access and species rich areas like the Amazon. Threatened and unique areas are disproportionately absent from Colombias protected lands. We highlight six biomes in Colombia as conservation priorities that should be considered in any future expansion of Colombias protected area network. Two of these biomes have less than 3% of their area protected and more than 70% of their area transformed for human use. One has less than 3% protected and high numbers of threatened vertebrates. Three biomes fall in both categories. Conclusions Expansion of Colombias Protected Area Network should consider the current representativeness of the network. We indicate six priority biomes that can contribute to improving the representation of threatened species and biomes in Colombia.

Indices of movement behaviour: conceptual background, effects of scale and location errors

A fundamental step in the emerging Movement Theory is the description of movement paths, and the identification of its proximate and ultimate drivers. The most common characteristic used to describe and analyze movement paths is its tortuosity, and a variety of tortuosity indices have been proposed in different theoretical or empirical contexts. Here we review conceptual differences between five movement indices and their bias due to locations errors, sample sizes and scale-dependency: Intensity of Habitat use (IU), Fractal D, MSD (Mean Squared Distance), Straightness (ST), and Sinuosity (SI). Intensity of Habitat use and ST are straightforward to compute, but ST is actually an unbiased estimator of oriented search and ballistic movements. Fractal D is less straightforward to compute and represents an index of propensity to cover the plane, whereas IU is the only completely empirical of the three. These three indices could be used to identify different phases of path, and their path tortuosity is a dimensionless feature of the path, depending mostly on path shape, not on the unit of measurement. This concept of tortuosity differs from a concept implied in the sinuosity of BENHAMOU (2004), where a specific random walk movement model is assumed, and diffusion distance is a function of path length and turning angles, requiring their inclusion in a measure of sinuosity. MSD should be used as a diagnostic tool of random walk paths rather than an index of tortuosity. Bias due to location errors, sample size and scale, differs between the indices, as well as the concept of tortuosity implied. These differences must be considered when choosing the most appropriate index.

Abundance, Population Structure, and Conservation of Kinosternon scorpioides albogulare on the Caribbean Island of San Andrés, Colombia

ABSTRACT We estimated population sizes, densities, structure, and the sex ratio of a locally endangered species of mud turtle, Kinosternon scorpioides albogulare, on the Caribbean island of San Andrés, Colombia. We estimated the population size at 4343 turtles on the island in 2002, inhabiting both freshwater ponds and mangroves. Densities for the main populations varied from 77 to 254 turtles/ha. The population structure showed that most of the individuals belong to intermediate size classes (110- to 140-mm carapace length) and a few belong to the smaller or larger size classes (< 110- or > 140-mm carapace length). The sex ratio was significantly different from 1:1 and was skewed toward females, 1 male per 1.97 females. No common use was found for the species among native islanders, although people from the continent living on the island use it for diverse purposes. Some threats were identified, such as mangrove pollution and the presence of the introduced species Tupinambis teguixin.

Abundance, Home Range, and Movement Patterns of the Endemic Species Dahl's Toad-Headed Turtle (Mesoclemmys dahli) in Cesar, Colombia

Abstract Population monitoring and evaluation of spatial requirements of species are key actions for the conservation of wild populations, especially for endemic and threatened species. We estimated the abundance of the endemic species Mesoclemmys dahli in 2 streams in Cesar, Colombia, from February 2008 to February 2009, by using aquatic sampling. We monitored fluctuations in abundance through the year and used mark–recapture sampling and the Jolly–Seber model to estimate population size and density. Home ranges and movement patterns were studied by using very high frequency (VHF) radio telemetry. We calculated home ranges for the year and for the wet and dry season independently. Estimated population size for the 2 streams varied during the year from 16 (95% CI, 7–30) to 175 (95% CI, 32–298) turtles. Densities ranged from 16 turtles/ha in April to approximately 170 turtles/ha in June, which is lower than other populations of M. dahli in Colombia as well as other South American chelids. Individuals captured during the wet season had a significantly higher mean body mass than those captured during the dry season, which suggests that larger animals may leave the streams during the dry months or that animals may lose weight during this period. Home ranges for 1 year varied from 1.6 to 30.8 ha when using the minimum convex polygon method and from 9.2 to 22.5 ha when using the fixed kernel density estimator. There were no significant differences in the mean movements during the dry and wet seasons. However, the greatest movements were documented either during the transition from wet to dry months or during the dry months. Conservation of M. dahli will require protection of the few streams where it occurs, as well as the associated riparian vegetation and surrounding areas used by the species.

Range extension of Kinosternon dunni Schmidt, 1947 (Reptilia, Testudines, Kinosternidae) in Chocó, Colombia

Dunns’ mud turtle Kinosternon dunni is recognized only from a few localities in the drainages of the San Juan, Baudo and Docampado Rivers in Choco, Colombia. We report on the occurrence of the species in three new localities in a different drainage, two in the Atrato River drainage, which flows into the Caribbean Sea, and a third locality in the Gulf of Uraba, in the Colombian Caribbean. These new records extend the range of the species approximately 367 km to the north of the closest previous confirmed record.

Research and Conservation Priorities for Tortoises and Freshwater Turtles of Colombia

The objective of our study was to review and quantify the level of knowledge of the biology of tortoise and freshwater turtle species of Colombia based on studies conducted in the country. We used the resulting rankings in knowledge, in combination with IUCN threat category, presence in protected areas, and endemism, to propose conservation priorities. This process also allowed us to evaluate which aspects of turtle biology have been least studied. Four species obtained total values of zero or one over the 21 knowledge criteria employed, so they were ranked as the highest priority for research based on the lack of knowledge of their biology: Black-lined Toad-headed Turtle (Mesoclemmys raniceps), Amazon Toad-headed Turtle (Mesoclemmys heliostemma), Gibba Toad-headed Turtle (Mesoclemmys gibba), and Dunn’s Mud Turtle (Kinosternon dunni). Moreover, species in the family Chelidae in general were found to have limited levels of knowledge, which makes this group a priority for investigation. Evaluation of the distinct criteria used in the knowledge assessment revealed that the best-known criteria were geographic distribution (modeled), presence or absence in protected areas, and clutch size. The most poorly known biological characteristics, which constitute research priorities, are the frequency of nesting, longevity and generation time, and population parameters. According to the criteria used, the priority species for conservation were the Magdalena River Turtle (Podocnemis lewyana), Dahl’s Toad-headed Turtle (Mesoclemmys dahli), K. dunni, and Maracaibo Wood Turtle (Rhinoclemmys diademata), three of which are endemic or semiendemic (R. diademata only occurs in Colombia and Venezuela), followed by two species of Mesoclemmys.

Genetic evidence of fragmented populations and inbreeding in the Colombian endemic Dahl’s toad-headed turtle ( Mesoclemmys dahli )

Population fragmentation is one of the most concerning consequences of habitat fragmentation, as small and isolated populations suffer increased genetic drift and inbreeding. However, the extent to which habitat fragmentation leads to population fragmentation depends not only on the landscape structure, but also on the response of organisms to it. This behavioral component makes it difficult to detect population fragmentation even if the habitat is fragmented, unless appropriate tools are used. In this study, we used a molecular approach to evaluate if Dahl’s toad-headed turtle (Mesoclemmys dahli) population was fragmented, given that it occurs in a very restricted area within the most degraded biome of Colombia, the tropical dry forest. We developed a panel of 15 microsatellite loci in order to perform the first genetic assessment of M. dahli across its complete geographic range. We found that M. dahli has significant genetic structure with at least four subpopulations, with surprisingly moderate to high levels of genetic diversity. Despite high levels of genetic diversity, subpopulations are very small (effective population sizes < 50) and isolated, with little to no contemporary gene flow among them. As a consequence, mating among related individuals has been occurring, and all four populations are showing high degrees of inbreeding. To counteract this threat, we recommend an urgent genetic rescue strategy accompanied by habitat restoration, and advocate for a new conservation status assessment, not based on geographic range, but on adult population size and level of fragmentation.