CONECTIVIDADE FUNCIONAL E A IMPORTÂNCIA DA INTERAÇÃO ORGANISMO-PAISAGEM*

The effects that changes on landscape spatial patterns have on ecological processes are of great importance due to the increasing rate of human modifications on the landscape, such as habitat fragmentation and habitat loss. Landscape connectivity, the opposite of fragmentation, determines the degree to which a landscape facilitates or restricts the movement of organisms between habitat patches. It influences population survivorship and dynamics on fragmented landscapes. With the development of Landscape Ecology, different indices for estimating landscape connectivity appeared. Some indices were criticized because of their redundancy, sensibility to scale, and because they measured only physical aspects of the landscape. Several authors have called attention on the importance of considering organism-landscape interactions when studying connectivity. There is a difference between structural connectivity, which considers only physical aspects of the landscape, and functional connectivity, which considers species-landscape interactions. Functional connectivity is a variable dependent on the vagility of the organism. Research priorities should focus on studying species-specific behavioral aspects, and making a link between these traits and landscape connectivity. Graph theory appears as a useful tool for studying functional connectivity. It allows for the use of species specific traits, and it helps on decision making for increasing landscape connectivity.Devido à crescente taxa de modificações antrópicas na paisagem, que resultam na fragmentação e perda de habitat, é importante estudar os efeitos que mudanças na configuração espacial têm nos processos ecológicos. A conectividade, o inverso da fragmentação, determina o grau no qual uma paisagem facilita ou restringe o movimento dos organismos entre fragmentos. Ela influencia a sobrevivência das populações e a dinâmica populacional em paisagens fragmentadas. Com o desenvolvimento da Ecologia da Paisagem apareceram diversos índices para medir o isolamento ou conectividade da paisagem. Alguns dos índices foram criticados por serem redundantes, sensíveis à escala, e por medir aspectos estritamente estruturais da conectividade. Diversos autores têm chamado a atenção sobre a importância de considerar a interação entre o organismo e a estrutura da paisagem para avaliar a conectividade. Existe uma diferença entre conectividade estrutural, que só considera aspectos físicos da paisagem, e conectividade funcional, que leva em conta a interação organismo-paisagem. A conectividade funcional é uma variável dependente da capacidade de dispersão do organismo. As prioridades de pesquisa devem ser enfocadas em estudar aspectos comportamentais próprios de cada espécie e fazer uma ligação entre estas características específicas e a conectividade da paisagem. A teoria dos grafos é uma ferramenta útil, que permite usar informação biológica de cada espécie e tomar decisões para melhorar a conectividade funcional da paisagem

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

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 Colombia's protected area network with global conservation priorities, and the extent to which the network reflects the country's 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 Colombia's protected lands. We highlight six biomes in Colombia as conservation priorities that should be considered in any future expansion of Colombia's 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 Colombia's 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

Geographic Distribution of the Tortoises and Freshwater Turtles of Colombia and their Representation in the Protected Area Network

<p>Colombia has a remarkable diversity of tortoises and freshwater turtles. However, a considerable portion of these species is threatened, and for others there is not enough information to make an adequate evaluation of their conservation status. This study is a first approximation to the quantitative evaluation of the geographic distribution of Colombia’s non-marine chelonians. Based on records of occurrence for each species, we evaluated the geographic distribution using statistical models (Maxent), hydrological basins, and the extent of occurrence and area of occupancy. Based on the presence data and the models, we studied the representation of each species in National Natural Parks (NNP), which correspond to the most rigorous conservation category of IUCN classification in Colombia, and other types of protected areas such as Private Reserves. We generated distribution models and estimated the area (km2) for 25 out of 27 species in the country. This information will be valuable for updating and evaluating the threat categories at the national level. The areas with the highest species richness correspond to the riverine ecosystems of the Amazon and Orinoco river basins and the Caribbean region, particularly the western Caribbean. This region is a top priority not only because of its richness but<br />also because of the presence of endemics and its high level<br />of threat. Only 56 % of the species have confirmed records<br />within National Parks. A greater portion could be present in these areas according to the statistical models, but only ten of those species would have more than 10 % of their ranges within a park’s boundary. Although the resulting models have certain limitations due to the nature of the data and analyses, they can be a starting point for research on the occurrence of turtles in NNP. Endemic species are poorly represented in protected areas, both in NNP and in other categories. Thus, protected areas that can assure the persistence of their populations are urgently needed.</p><p><strong><br /></strong></p><p><strong>Distribución geográfica de las tortugas continentales de Colombia y su representación en áreas protegidas</strong></p><p>Colombia cuenta con una alta diversidad de quelonios continentales, sin embargo, un número considerable de especies<br />se encuentran amenazadas y para otras no existe información suficiente para evaluar su estado de amenaza. Este trabajo es una aproximación cuantitativa al estudio de la distribución  geográfica de las tortugas continentales de Colombia. Con base en registros de localidades con presencia de cada especie, evaluamos la distribución geográfica a partir de modelos estadísticos (Maxent), cuencas hidrográficas, extensión de presencia y área de ocupación. Estimamos la representación de<br />cada especie en el sistema de Parques Nacionales Naturales (PNN) y en otras áreas del sistema nacional de áreas protegidas,<br />incluyendo Reservas Naturales de la Sociedad Civil (RNSC). Se construyeron modelos de distribución geográfica y se estimó<br />el área de distribución (km2) para 25 de las 27 especies presentes en el país. Las áreas con mayor riqueza de especies son los ecosistemas ribereños de la Amazonia, Orinoquia y el Caribe, en particular el Caribe occidental. Este último es un bioma prioritario debido a su alto número de endemismos y por la amenaza que enfrentan sus especies. Solo el 56 % de las especies estudiadas presentan registros confirmados en los PNN. Un mayor número de especies podría estar presente en los PNN de acuerdo con los resultados de los modelos, pero solo diez especies tendrían más del 10 % de su distribución representada en dichas áreas. Los modelos generados podrán ser un punto de partida para investigar la presencia de quelonios en los PNN.<br />Las especies endémicas están pobremente representadas en las áreas protegidas, tanto en los PNN como en otras categorías,<br />por lo que es urgente constituir nuevas áreas protegidas para asegurar la supervivencia de sus poblaciones.</p><p> </p

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

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, Baudó and Docampadó Rivers in Chocó, 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 Urabá, 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