What’s environmentally good for one area may be an environmental disaster for an adjacent area

Shift in nesting ground of the long-legged buzzard (Buteo rufinus) in Judea, Israel – An effect of habitat change

Guilad Friedmann, Yoram Yom-Tov, Uzi Motro and Yossi Leshem

Biological Conservation
Volume 144, Issue 1, January 2011, Pages 402-406

Here is a good paper from Israel that I came across recently. It deals with afforestation in an area and its unintended effect on the environment.

Tel Aviv University researchers, Guilad Friedmann, Yoram Yom-Tov, Uzi Motro and Yossi Leshe after extensive research says planting a new forest is a venture that is fraught with lot of ecological imponderables. Indigenous species tend to migrate to neighboring habitats and what’s environmentally good for one may be detrimental for another one.

Friedemann et al studied two raptor species in the Judean Foothills, the long-legged buzzard and the short-toed eagle. The long-legged buzzard’s habitat is the open spaces of the Judean Mountains. They use the mountain cliffs for nesting and hunting. The afforestation scheme launched by the forest department forced the long-legged buzzards to migrate elsewhere. They have relocated themselves to the trees of the Judean Foothills which in turn has threatened the nesting ground and food source of the short-toed eagle, its original inhabitants.

The researcher tracked the movements of both species throughout breeding season by tagging four buzzards and three eagles. He analyzed the food remains to determine the extent of competition for food sources between the two raptor species.

The results clearly indicated that the buzzards have usurped the eagles' habitat. The eagles were losing out.

Here is a case where afforestation, instead of a positive contribution to the environment, was the cause of habitat destruction. This should serve as a cautionary note for us. Detailed impact studies need to be done before we embark on any ambitious project. The researcher says a broader consideration of not just of the directly affected area, but of neighboring areas as well needs to be taken in to account. He adds that in this case, harm might have been avoided by setting aside a swathe of land where the buzzards could continue to nest and hunt. This conclusion has broad implications for our landscape planning and policy implementation. 

Improving the reliability of Individual animal identification based on Camera-Trapping Data

A Novel Method to Improve Individual Animal Identification Based on Camera-Trapping Data

EDUARDO MENDOZA, PIERRE R. MARTINEAU, ELLIOTT BRENNER, RODOLFO DIRZO.

The Journal of Wildlife Management 75(4):973–979; 2011; DOI: 10.1002/jwmg.120

Picture-based individual identification of animals is largely based on ad hoc protocols. This in turn tends to strongly rely on human visual inspection of pictures.  Mis-identification can produce significant biases in population estimates. In the paper referred to above the researchers present a novel method to improve individual identification of animals based on camera-trapping data. Application of their method to bobcat (Lynx rufus) resulted in a marked increase (300%) in agreement between classifiers.

An initial ARI value of 0.28 increased to a final value of 0.84 (1 ¼ maximum agreement). In contrast, comparisons involving random picture groupings consistently rendered low ARI values (<0.05). The numbers of individuals named by the 2 users decreased from initial values of 46 and 43 to final values of 25 and 29, respectively.

The researchers sign off saying “tool presented here will help researchers and wildlife managers to identify individual mammals and monitor populations.”

I thank, Dr Eduardo Mendoza, for graciously sending me a copy of the paper

Science as a tool to guide conservation prioritization

Using science to guide conservation: From landscape modelling to increased connectivity in the Taita Hills, SE Kenya

Mwangi Githiru, Luc Lens,Frank Adriaensen, James Mwang’ombe and Erik Matthysen

Journal for Nature Conservation
Article in Press, Available online 12 June 2011

Communication gaps between scientists, stakeholders and policy makers make using of science knowledge to guide conservation difficult. In this paper the researchers demonstrate how they have managed to integrate scientific knowledge into consensually formulated conservation actions in the Taita Hills, Kenya.

The scientist used GIS-based least-cost modelling, together with sociological and forest characteristics  to determine and prioritize the most appropriate areas for reforestation from a set of exotic forest plantations targeted for conversion into indigenous forests.

This prioritisation was done through a succession of three workshops. The workshops were conducted on site). The Views of multiple stakeholders were heard to build consensus on conservation actions, and formulate an implementation policy.

The researchers say the key lesson they  learned from this exercise was that bridging the gap between science and conservation demands a very open, inter-disciplinary strategy, initiated and executed jointly by a diverse group of people that includes the Government (policy-makers and implementers), NGOs (conservationists and environmental advocates), scientists (researchers), conservationists and the local community.

The researchers signs off with the following comment. “This study provides a pointer for what it may take to integrate human issues with sustained environmental management based on scientific knowledge.”

The IUCN Annual Lake Swim

The IUCN Annual Lake Swim is taking place today (3rd August). The IUCN Annual Lake Swim began in 2006 when Jane Smart of IUCN swam across the lake together with Liz Radford of Plantlife, in memory of environmentalist and former IUCN Council Member Richard Sandbrook in aid of WaterAid. With the arrival of Julia Marton Lefèvre as Director General in 2007, the event was enthusiastically adopted as an annual one. The team of swimmers from IUCN crosses the lake each year in aid of a good cause and in celebration of the beauties of nature.

In 2011 IUCN will be raising funds in aid of The People of Japan following the tragic events which took place in March of this year. This year’s swim will raise  funds for the Red Cross Society of Japan. All the funds raised will go directly to the people affected on the ground. For donations please visit the following link: http://www.indiegogo.com/IUCN-Annual-Lake-Swim-2011.

The swim is from Nernier in France to Prangins, near Nyon in Switzerland. The distance is 4.24 km - although in reality the distance will be nearer 6 km - because it is never possible to swim in a completely straight line!

This year’s swimmers are:
Jane Smart, Captain
Mette Bovenschulte
Suzan Craig
Chloe Hill
Julia Marton-Lefèvre
Lilly Powell (Jane’s daughter)
Trevor Sandwith
Laura Seidl (Andy’s wife)
Claire Warmembol

The captains will be Bertrand de Montmollin, Chair of the Swiss National Committee for IUCN and Chair of the IUCN SSC Mediterranean Island Plant Specialist Group, and Christian Laufenberg.  They will be accompanied by first mates Kaori Yasuda and Poppy Powell (Jane’s 2nd daughter).

Biological process of dispersal – When it comes to urban fox the moms decide who should be chucked out

Mother Knows Best: Dominant Females Determine Offspring Dispersal in Red Foxes (Vulpes vulpes)

Helen M. Whiteside, Deborah A. Dawson, Carl D. Soulsbury, and Stephen Harris

Based on their 33 years of field study aided with DNA inputs, researchers Helen M. Whiteside, Deborah A. Dawson, Carl D. Soulsbury, and Stephen Harris have come to the conclusion that dominant mothers in urban fox (Vulpes vulpes) played a key role in shaping the group dynamics of the mammals. They decide which cubs get to stay and which ones must leave the group and find a new territory. This study is claimed to be the first study to identify the importance of juvenile dispersal among social mammals.

The researchers experienced lot of difficulty to work out family trees. Combining data collected in the field with DNA paternity testing allowed the team to overcome the difficulty.

The team worked out dispersal strategy based on the male cubs' genetic relationship with the dominant female. The researchers say it is an out-breeding mechanism, which stops them breeding with their mothers and cub dispersal appeared to be much more important for female foxes than males. The researchers say “Relatedness to the dominant male had no effect on dispersal in offspring of either sex, whereas there was a strong effect of relatedness to resident females on offspring dispersal independent of population density. Males with dominant mothers dispersed significantly more often than males with subordinate mothers, whereas dispersing females were significantly more likely to have subordinate mothers compared to philopatric females.”

The researchers sign off underlining the fact that their research provides a unique opportunity to advance our understanding of the key biological process of dispersal

The paper which appears in Plos One is an open access document 

The significance of visual ‘nectar guides’

Floral signposts: testing the significance of visual ‘nectar guides’ for pollinator behaviour and plant fitness

Dennis M. Hansen,Timotheüs Van der Niet and Steven D. Johnson

Published online before print July 27, 2011, doi:10.1098/rspb.2011.1349Proc. R. Soc. B

Yesterday we were  discussing about the leaves that act like neon signs in restaurants. Here is another feature that is akin to what we were discussing. This time it is nectar guides, contrasting patterns on flowers that direct pollinators towards a concealed nectar reward.

The researchers experimentally investigated the role of nectar guides in a natural system, the South African iris Lapeirousia oreogena, whose flowers have a clearly visible pattern of six white arrow markings pointing towards the narrow entrance of the long corolla tube. The sole pollinator is a long-proboscid nemestrinid fly.

The investigators painted over none, some or all of the white arrow-markings with ink that matched the colour of the corolla background. Aarrow-marking removal had little effect on the approaches by flies to flowers from a distance, but it significantly, and according to the words of the researchers dramatically reduced the likelihood of proboscis insertion. The researchers say export of pollen dye analogue (an estimate of male fitness) was reduced to almost zero in flowers from which all nectar guides had been removed, and fruit set (a measure of female fitness) was also significantly reduced. 

According to the researchers their experiments confirm that the markings on L. oreogena flowers serve as nectar guides and suggest that they are under strong selective maintenance through both male and female fitness components in this pollination system.

Leaves that act like neon signs in restaurants

Floral Acoustics: Conspicuous Echoes of a Dish-Shaped Leaf Attract Bat Pollinators

Ralph Simon,Marc W. Holderied,Corinna U. Koch,Otto von Helversen

Science 29 July 2011: 
Vol. 333 no. 6042 pp. 631-633 
DOI: 10.1126/science.1204210

Restaurants usually have eye catching neon signs to attract customers. Researchers have come up with an analogy from the natural word. Scientists have just described the behavior of a vine (Marcgravia evenia ) found in Cuban jungle, that puts forth unusual dish-shaped leaf displayed above the inflorescences to attract bats.

The special leaf makes the wine more conspicuous to the sonar of bats and acts like a dish reflector. This leaf’s echoes fulfilled requirements for an effective beacon.  They were strong and multidirectional

According to the researchers this is an interesting example of the ongoing coevolution of flowering plants and their animal pollinators,

All is not well with protected area networks says researchers

Ongoing global biodiversity loss and the need to move beyond protected areas: a review of the technical and practical shortcomings of protected areas on land and sea

Camilo Mora and Peter F. Sale

MARINE ECOLOGY PROGRESS SERIES

Mar Ecol Prog Ser

Vol. 434: 251–266, 2011

doi: 10.3354/meps09214

Here is a thought provoking paper on, protected areas and its effectiveness. The researchers relied on a broad range of data and a review of the literature to show that the effectiveness of existing, and the current pace of the establishment of new, protected areas will not be able to overcome current trends of loss of marine and terrestrial biodiversity.

The authors say there are significant shortcomings in the usual process of implementation of protected areas. They go on to add that the shortcomings include techni-cal problems associated with large gaps in the coverage of critical ecological processes related to individual home ranges and propagule dispersal, and the overall failure of such areas to protect against the broad range of threats affecting ecosystems. They stress the point that budget constraints, conflicts with human development, and a growing human population that will increase not only the extent of anthropogenic stressors but the difficulty in successfully enforcing protected areas.

The authors sign off with these words  “Whileefforts towards improving and increasing the number and/or size of protected areas must continue, there is a clear and urgent need for the development of additional solutions for biodiversity loss, particularly ones that stabilize the size of the world’s human population and our ecological demands on biodiversity”

The first "true mammal" to sense prey by their electric fields

Electroreception in the Guiana dolphin (Sotalia guianensis)

Nicole U. Czech-Damal, Alexander Liebschner,Lars Miersch,Gertrud Klauer,Frederike D. Hanke,Christopher Marshall,Guido Dehnhardt,and Wolf Hanke

Published online before print July 27, 2011, doi:10.1098/rspb.2011.1127 Proc. R. Soc. B

The South American  Guiana dolphin (Sotalia guianensis) has just been described as the only  "true mammal" to sense prey by their electric fields. Even though Electroreception is well known in fish and amphibians, till now the only mammal example was the platypus.

In the paper referred to above the scientists  show that the hairless vibrissal crypts on the rostrum of the Guiana dolphin, structures originally associated with the mammalian whiskers, serve as electroreceptors in Guiana dolphin.

The researchers recorded a sensory detection threshold for weak electric fields of 4.6 µV cm⁻¹, which is comparable to the sensitivity of electroreceptors in platypuses.

Now the researchers plan to investigate whether other cetaceans possess the same ability.

Spatially balanced acoustic surveys for bats

A practical sampling design for acoustic surveys of bats

Thomas J. Rodhouse, Kerri T. Vierling, Kathryn M. Irvine

Wildlife Management - Article first published online: 21 APR 2011

Acoustic surveys are regularly put to use to find out bat occurrence and activity patterns. It comes in very handy for addressing concerns for habitat management, wind energy, and disease on bat populations. 

When a probabilistic sample is required for drawing inference to unsampled areas,  devising these surveys becomes a wee bit difficult. Sampling frame errors and other logistical constraints often makes it essential for survey sites to be dropped from the sample and new sites added. Here crops up difficulties.

The authors of this paper say spatially balanced sampling designs recently developed to support aquatic surveys along rivers provide solutions to a number of practical challenges faced by bat researchers. These techniques allow sample site additions and deletions, support unequal-probability selection of sites, and provide an approximately unbiased local neighborhood-weighted variance estimator that is efficient for spatially structured populations such as bats.

Taking cue from the above mentioned technique the researchers implemented a spatially balanced design to survey canyon bat (Parastrellus hesperus) activity along a stream network. This provided leeway for typical logistical challenges and yielded a 25% smaller estimated standard error for the mean activity level than the usual simple random sampling estimator.

The authors signs off like this  “Spatially balanced designs have broad application to bat research and monitoring programs and will improve studies relying on model-based inference (e.g., occupancy models) by providing flexibility and protection against violations of the independence assumption, even if design-based estimators are not used. Our approach is scalable and can be used for pre- and post-construction surveys along wind turbine arrays and for regional monitoring programs.”

Book Recommendation

Trophic Cascades

Predators, Prey, and the Changing Dynamics of Nature

John Terborgh, James Estes

Publisher: Island Press
456 p. 7"x10"
ISBN: 9781597264877

Here is a very good book on Trophic cascads, the top-down regulation of ecosystems by predators. Trophic cascades are often turned topsy-turvy by human interventions. The book bucks the idea of "bottom up" regulation of ecosystems. It graphically describes the consequences of apex predator elimination which results in a chain reaction, or "cascade" of effects down to the lowest level of the trophic ladder.

In recent years Trophic cascads have started assuming increasing influence in the development of conservation and management strategies.

Marco Polo Sheep is an international traveller

An analysis of DNA from fecal samples by researchers from WCS has come up with the finding that Marco Polo sheep in the Pamir Mountains of Afghanistan are genetically connected to sheep in neighboring Tajikistan and China, despite the difficult terrain.

The researchers involved are Dr Richard.B. Harris of the University of Montana, Dr John Winnie, Jr.of Montana State University, Dr Gordon Luikart, Stephen, Dr J. Amish, and Dr F.W. Allendorf of the University of Montana, and Dr Albano Beja-Pereira, Vânia Costa, and Dr Raquel Godinho of the Universidade do Porto

The research team collected fecal samples from 172 individual sheep from five different areas in Afghanistan, Tajikistan to arrive at their conclusions.

The research highlighted the fact that non-invasive methods of determining population trends and relatedness are extremely valuable in devising conservation strategy for animals that are elusive and difficult to track. It also highlighted the need for international cooperation between Afghanistan, Tajikistan, and China.

Long-term preventive conservation is preferable to short term firefighting

When should we save the most endangered species?

Howard B. Wilson,Liana N Joseph,Alana L. Moore and Hugh P. Possingham

Article first published online: 12 JUL 2011

Ecology Letters (2011)

In this paper the authors emphasizes that long-term preventive conservation measures are far better than short term firefighting

Conservationists have always been bothered whether to give priority to cost-effective actions or whether focusing solely on the most endangered species will ultimately lead to preservation of the greatest number of species. Conservation funding tends to be short-term in nature and on the whole biased to more endangered species.

By framing this debate within a decision-analytic framework, the researchers show that allocating resources solely to the most endangered species will typically not minimise the number of extinctions in the long-term, as this does not account for the risk of less endangered species going extinct in the future.

Short term fire fighting can be resorted to when our planning timeframe is short or we have a long-term view and we are optimistic about future conditions.

On the whole this paper is very thought provoking.

Connectivity, patch based graphs, and conservation

Patch-based graphs of landscape connectivity: A guide to construction, analysis and application for conservation

Paul Galpern Micheline Manseau and Andrew Fall

Biological Conservation
Volume 144, Issue 1, January 2011, Pages 44-55

Here is a good paper that deals with connectivity and the use of patch based graphs.

Connectivity is a major conservation priority. Maintaining connectivity and mitigating the fragmentation of habitat is critical for landscape processes. For modelling the functional connectivity of landscapes, Graph theory (also known as network analysis), has become sine qua non for many researchers and managers.  The authors of this paper say they conducted a review of studies that use graph theory to model connectivity among patches of habitat (patch-based graphs), with the intention of identifying typical research questions and their associated graph construction and analysis methods.

The researchers identified and examined nine questions of conservation importance that can be answered with these types of graph models. They discussed appropriate applications of these questions and presented a guide for using graph methods to answer them. They also examined how the connectivity predictions of patch-based graphs have been assessed and emphasize the importance of empirical evaluation.

The researchers sign off like this “. Our findings identify commonality among diverse approaches and methodological gaps with an aim to improve application and to help the integration of graph theory and ecological analysis.”  “As a final caveat, we urge those using patch-based graphs in a decision-making process to assess the relative importance of conserving connectivity compared to, for example, conservation decisions based only on the amount and quality of habitat. This remains an important area for further theoretical and empirical consideration”

Snap-buckling observed in vertebrates for the first time

Snap-buckling is usually seen in plants and insects. It is akin to the opening and closing of a snap hair clip

 The best example of snap-buckling in plants is the Venus flytrap, which uses it to catch insects.

For the first time Snap-buckling has been observed in vertebrates and it happens to be in hummingbird.

Hummingbird beaks are built to feed on flowers, but hummingbirds can't live on nectar alone. To get enough protein and nutrients they need to eat small insects also. The shape of a hummingbird's beak allows for “controlled elastic" and this allows it to snatch up flying insects in a mere fraction of seconds.

The researchers found that the hummingbird's bendy lower beak flexes by as much as 25 degrees when it opens. At the same time it also widens at the base to create a larger surface for catching insects. The extra speed leads to greater success in catching insects.

Details of the study will appear in the August 7 issue of Journal of Theoretical Biology

Conservation success story - Grand Cayman blue iguana is back from the brink of extinction

         Credit: Julie Larsen Maher/Wildlife Conservation Society.

We constantly hear about species on the brink of extinction. In many cases efforts to save them seem a distant possibility. Here is a rarity in conservation, a conservation effort that bucks the trend.

Blue Iguana Recovery Program in Cayman Island is well on its way to success. Blue iguana is the largest native species of Cayman Island. Coordinated by the National Trust for the Cayman Islands, the Blue Iguana Recovery Program—a consortium of local and international partners—has successfully released more than 500 captive-bred reptiles since the initiative's inception in 2002. In 2002 wild population of iguanas numbered less than two dozen. Conservationists expect to reach their goal of 1,000 iguanas in managed protected areas in the wild in a few years.


Recovery efforts to save the Grand Cayman blue iguana have mostly centered on the Salina Reserve, a 625-acre nature reserve located on the eastern side of the island. This year the efforts move on to newly established Colliers Wilderness Reserve also.

The importance of survey design in distance sampling

The importance of survey design in distance sampling: field evaluation using domestic sheep
Tom A. Porteus, Suzanne M. Richardson, and Jonathan C. Reynolds

Wildlife Research 38(3) 221-234 http://dx.doi.org/10.1071/WR10234

Wildlife managers and researchers regularly use distance sampling. Here is a paper that emphasizes the importance of survey design in distance sample. Management decisions are often made based on these estimates. Without knowledge of true population size it is not possible for wildlife biologists to evaluate how biased the estimates can be if survey design is compromised.

Here the researchers did a clever field evaluation using domestic sheep. Their aims were to use distance sampling to estimate population size for domestic sheep free-ranging within large enclosed areas of hill country. By comparing estimates against actual numbers, they examined how bias and precision are impaired when survey design is compromised

Both line and point transect sampling were used to derive estimates of density for sheep on four farms in upland England. In Stage I they used limited effort and different transect types to compromise survey design. In Stage II they increased effort in an attempt to improve on the Stage I estimates. They also examined the influence of a walking observer on sheep behaviour to assess compliance with distance sampling assumptions and to improve the fit of models to the data.

The results clearly demonstrated that distance sampling can lead to biased and imprecise density estimates if survey design is poor, particularly when sampling high density and mobile species that respond to observer presence. The researchers say in Stage I, walked line transects were least biased; point transects were most biased. Increased effort in Stage II reduced the bias in walked line transect estimates. For all estimates, the actual density was within the derived 95% confidence intervals, but some of these spanned a range of over 100 sheep per km².

The researchers have clearly shown that survey design is vitally important in achieving unbiased and precise density estimation using distance sampling. Adequate transect replication reduced the bias considerably within a compromised survey design.

The researchers sign off like this “Management decisions based on poorly designed surveys must be made with an appropriate understanding of estimate uncertainty. Failure to do this may lead to ineffective management.”

Tailpiece: We had sent mail to one wildlife warden regarding the poor design of some of his census techniques. We had also requested him to contact well versed scientists to set things right. He never responded. This post is intended to show him and his ilk how design flaws can throw the entire process out of kilter.

Sexual segregation in Giant Pandas

Different habitat preferences of male and female giant pandas

Dunwu Qi,Shanning Zhang,Zejun Zhang,Yibo Hu,Xuyu Yang,Hongjia Wang,Fuwen Wei

Article first published online: 5 JUL 2011 Journal of Zoology

DOI: 10.1111/j.1469-7998.2011.00831.x

Now here is a surprise. According to this study male and female giant pandas prefer to use different habitats. Using a combination of field surveys and sex identification through fecal DNA, the researchers investigated gender differences in habitat use in wild giant pandas through ecological niche factor analysis modelling. 

Female pandas frequent high altitude conifer forests and mixed forests on steeper slopes, whereas males roam about more widely, researchers discovered. Females stuck to these areas as they provide den sites for birthing and dense bamboo cover in which baby pandas can hide.

The researchers say these findings should be taken into account when breeding programmes for release of giant pandas back into the wild are devised.

First insights into Sumatran tiger–prey temporal interactions

Assessing tiger–prey interactions in Sumatran rainforests

M. Linkie AND M. S. Ridout

Journal of Zoology

Volume 284, Issue 3, pages 224–229, July 2011

Very little is known about Sumatran tiger–prey temporal interactions. Here the researchers are trying to unravel the mystery surrounding   Sumatran tiger ( Panthera tigris Sumatra)

The researchers quantify temporal overlap between the Sumatran tiger and five of its presumed prey species. This was from four study areas comprising disturbed lowland to primary submontane forest data from 126 camera traps.  Over 8984 camera days were used to estimate species activity patterns and, the overlap through the coefficient Δ (ranging from 0 to 1, i.e. no overlap to complete overlap). 

To determine confidence intervals associated with respective overlap a newly developed statistical technique was used.

Strong temporal overlap was found between tiger and muntjac Muntiacus muntjac (Δ=0.80, 95%CI=0.71–0.84) and tiger and sambarCervus unicolor (Δ=0.81, 0.55–0.85).

The authors signs off like this “ According to the foraging theory, Sumatran tigers should focus on expending lower levels of energy searching for and then capturing larger bodied prey that present the least risk. Hence, surprisingly, there was little overlap between the crepuscular tiger and the largest-bodied prey species available, the nocturnal tapir Tapirus indicus (0.52, 0.44–0.60), suggesting that it is not a principal prey species. This study provides the first insights into Sumatran tiger–prey temporal interactions. The ability to estimate overlap statistics with measures of precision has obvious and wide benefits for other predator–prey and interspecific competition studies.”