Category Archives: Uncategorized

The Connectivity Analysis Toolkit is a software interface that provides conservation planners with tools for both linkage mapping and landscape-level ‘centrality’ analysis. 450 people from around the world have downloaded the CAT since it became available in 2010.
We have just released Version 1.2 with the following changes:

• Approximate shortest-path betweenness centrality allows faster computation of this metric
• Approximate current flow betweenness centrality allows faster computation of this metric; function also uses sparse matrices for lower RAM requirements
• Network flow functions updated to LEMON version 1.2.2
• Updates to manual and tutorial dataset

These are major updates which speed computation in some cases by an order of magnitude. Thanks to Aric Hagberg for his work adding these new functions to NetworkX and thus making them available for the CAT.

The software is freely available at www.connectivitytools.org (a link is also posted on this blog site).

Two new articles published in the Proceedings of the National Academy of Sciences discuss whether management can push forests and other ecosystems into ‘landscape traps’ which may be difficult to restore to former conditions. The ‘landscape trap’ concept resembles previous research on alternate stable ecosystem states, but recognizes the importance of spatial dynamics in maintaining a landscape in a degraded state. Continue reading →

A new report titled “Assessment & Planning for Ecological Connectivity: A Practical Guide” has been produced by a team of scientists convened by the Wildlife Conservation Society’s North America Program. The report can be downloaded here.

A new paper in the Journal Science by Chen and colleagues finds that species ranges are moving upward in elevation and towards the poles faster than has been expected from previous studies. Species’ ranges have climbed an average of 11 meters higher and 16.9 km closer to the poles per decade, with species in areas experiencing the greatest climate shift also showing the greatest range movement. Continue reading →

A new paper in Science by Jim Estes and colleagues reviews contemporary findings on the consequences of removing large apex consumers (e.g., top predators) from nature—a process they term trophic downgrading.
The authors highlight the ecological theory that predicts trophic downgrading, consider why these effects have been difficult to observe, and summarize the key empirical evidence for trophic downgrading. The paper concludes Continue reading →

A new paper by Maclean and Wilson in the journal PNAS compares threat of extinction, as documented by IUCN Red List data on recent changes in population and range size, with that predicted by previous studies that used models to predict the potential effects of climate change on extinction. The study is the most comprehensive to date in terms of examining data for a wide range of species worldwide. Observed extinction probabilities were similar to those predicted by models. The authors conclude that climate change: Continue reading →

A new study by Scott Nielsen, a researcher from the University of Alberta, examines whether conservation of important habitat for grizzly bears can also help achieve broader biodiversity goals. The paper is part of a special issue of the British Columbia Journal of Ecosystems Management. This issue of JEM also contains several articles describing other facets of the recently-completed ecoregional plan for BC’s Central Interior region. The plan, which covers a large portion of the province, is one the most comprehensive conservation planning examples from BC to date, integrating data on vegetation, terrestrial focal species, aquatic biodiversity, and other conservation foci.
The Nielsen study compared the distribution of predicted source and sink habitats for grizzly bears with areas found to be highly “irreplaceable” for achieving protection of other biodiversity features. The author concludes that “protection of grizzly bear source habitats across different bear density classes does provide a reasonable umbrella effect or shortcut for protection of other important conservation features in grizzly bear range.” However, Nielsen cautions that “If the highest density source habitats for grizzly bears were used for targeting future conservation areas, important areas of high biodiversity value for low-elevation plains between the mountain ranges would therefore be overlooked. This is particularly evident for the extirpated grizzly bear habitats in the Fraser Basin, where comparisons with grizzly bear habitats were not assessed yet contained noticeable areas of highly irreplaceable habitat (Loos 2011). This research therefore suggests that if grizzly bears are used as a focal surrogate species for conservation planning, source-like habitats across the range of bear density classes should be considered, as well as the extent of the analysis, to acknowledge that at larger extents the extirpated habitats common to low elevations will be overlooked, and yet are critical to the conservation of threatened biodiversity.”

The journal issue can be downloaded here.

A new paper (full paper here) by Compton et al. in Ecology Letters evaluates the costs to ecosystem services due to the many ways in which humans add excess nitrogen into the environment through both non-point sources such as agricultural runoff and point-source pollution from electrical utilities. The authors conclude that “Damage costs outweigh the costs associated with reducing N loading. This provides a strong rationale for mitigation of N pollution and the associated effects on ecosystem services. The fact that these initial estimates (Table 2) are incomplete means that our analysis almost certainly underestimates the societal benefits to mitigating the negative effects of nitrogen pollution.”

A new review by Curtis Flather and colleagues in the journal Trends in Ecology and Evolution questions the claim that there is a ‘magic number’ applicable across diverse taxa for setting a “minimum viable population” threshold below which a species is at high risk of extinction. The review has received some coverage in the media as implying that ambitious goals for recovery of endangered species are not supported by science. As an example, the media article cited “a coalition of environmental groups” who claimed that “to survive and thrive…the [wolf] population needed at least 2,000 and preferably 5,000 wolves.” But this conclusion misses the primary focus of Flather et al.’s review. Continue reading →

Much of what we do as scientists is based on the belief that our fellow citizens are ‘rational actors’, who just need access to good informatioon to make rational decisions. However, the recent debate over whether humans are altering the earth’s climate suggests to many that lack of information is not the problem. In a recent column in the magazine Mother Jones, Chris Mooney reports on studies which suggest that “people reject[…] the validity of a scientific source because its conclusion contradicted their deeply held views…that undercuts the standard notion that the way to persuade people is via evidence and argument. In fact, head-on attempts to persuade can sometimes trigger a backfire effect, where people not only fail to change their minds when confronted with the facts—they may hold their wrong views more tenaciously than ever.” Continue reading →