Economic Importance of Bats

 Diseases and increased development of wind-power facilities are threatening populations of insectivorous bats in many parts of the world. This past weekend I read an excellent paper on the economic importance of bats in agriculture and forestry. Even though the study is based in US it has implications worldwide.

Bats are voracious predators of nocturnal insects, spanning crop and forest pests. Their activity    decreases the need for pesticides. The researchers say a single colony of 150 big brown bats in Indiana eat nearly 1.3 million insects a year. They add that loss of bats in North America could lead to agricultural losses estimated at more than $3.7 billion/year.   Downstream impacts of pesticides on humans, domestic and wild animals and our environment are not included in this estimate.  The total value of bats to the agricultural industry is roughly estimated at $22.9 billion a year

The researchers issue this warning “Not acting is not an option because the life histories of these flying, nocturnal mammals -- characterized by long generation times and low reproductive rates -- mean that population recovery is unlikely for decades or even centuries, if at all,". They have made an impassioned plea for increased awareness of the benefits of insectivorous bats among the public, policymakers and scientists.

Economic Importance of Bats in Agriculture

Justin G. Boyles ,Paul M. Cryan,Gary F. McCracken, and Thomas H. Kunz

Science 1 April 2011:
Vol. 332 no. 6025 pp. 41-42
DOI: 10.1126/science.1201366 

More on disappearance of good taxonomists

A few days back we rued the collapse of taxonomic expertise worldwide. Against the backdrop of this sad phenomenon I found an excellent paper about the disappearance of good taxonomists and ways to overcome this. The paper is titled “Biological identifications through DNA barcodes” authored by Paul D. N. Hebert, Alina Cywinska, Shelley L. Ball and Jeremy R. deWaard

The paper is a wee bit old (2003) but what the researchers say has great relevance today. The researchers are convinced that the sole prospect for a sustainable identification capability lies in the construction of systems that employ DNA sequences as taxon ‘barcodes’.

The researchers emphatically conclude that mitochondrial gene cytochrome c oxidase I (COI) can serve as the core of a global bioidentification system for animals.

The researchers clearly demonstrate that COI profiles, derived from the low–density sampling of higher taxonomic categories, ordinarily assign newly analysed taxa to the appropriate phylum or order. Species–level assignments can be obtained by creating comprehensive COI profiles.

A model COI profile, created by the researchers based upon the analysis of a single individual from each of 200 closely allied species of lepidopterans, was 100% successful in correctly identifying subsequent specimens.

The researchers conclude that the current problem of species identification can be overcome by fully developed COI identification system. It will also provide a reliable, cost–effective and accessible solution. The authors sign off saying the assembly will generate important new insights into the diversification of life and the rules of molecular evolution.

Biological identifications through DNA barcodes

Paul D. N. Hebert, Alina Cywinska, Shelley L. Ball and Jeremy R. deWaard

 Proc. R. Soc. Lond. B February 7, 2003 270:313-321; doi:10.1098/rspb.2002.2218

Effects of patterns of mating success and juvenile survival probabilities on rates of genetic drift

Aline Magdalena Lee, Steinar Engen and Bernt-Erik Sæther have come up with a good paper titled “The influence of persistent individual differences and age at maturity on effective population size’ in the journal Proceedings of the Royal Society B.

Ratios of effective populations size, N_e, to census population size, N, are used by scientists to measure genetic drift in populations. These ratios are affected by factors like mating system and age at sexual maturation. 

The researchers used a stochastic matrix model and examined how different levels of persistent individual differences in mating success among males may affect N_e/N, and how this relates to generation time. These differences are shown to cause a lower N_e/N ratio than would be expected when mating is independent among seasons. 

The researchers found that both the direction and magnitude of the effect depends on the survival rate of juveniles in the population. When maturation is delayed, lowered juvenile survival causes higher levels of genetic drift. Predicted shifts in N_e/N with changing age at maturity are shown to be dependent on which of the commonly used definitions of census population size, N, is employed.

The researchers clearly demonstrate that patterns of mating success, as well as juvenile survival probabilities, have substantial effects on rates of genetic drift.

Published online before print March 24, 2011, doi:10.1098/rspb.2011.0283 Proc. R. Soc. B

Inexpensive and biodegradable thermoplastics from chicken feather

Researchers in USA have come up with a proposal to manufacture biodegradable thermoplastics from chicken feather.  The researchers processed chicken feathers and added a chemical known as methyl acrylate to turn them into a plastic. From this they made thin films which are more degradable and more sustainable. Another plus point is that the plastics are much more resistant to water.

 Poultry feathers are available in large quantities and this makes the proposal very attractive. The researchers claim that the feather-g-poly (methyl acrylate) developed showed good thermoplasticity, and feather films had substantially higher tensile properties than soy protein isolate and starch acetate films.

The tough and chemically stable protein keratin in feathers can lend strength while reducing weight in the mixtures of plastics chemicals known as composites. Feathers make up 50% of the new mass of the composite develped.

Tests on a grander scale will be necessary to assess the product in terms of economics and carbon footprint. The scientists are confident that this new proposal will come out with flying colors.

Graft Polymerization of Native Chicken Feathers for Thermoplastic Applications

Enqi Jin, Narendra Reddy, Zhifeng Zhu, and Yiqi Yang

J. Agric. Food Chem., 2011, 59 (5), pp 1729–1738

DOI: 10.1021/jf1039519

Interdisciplinary approaches for the management of existing and emerging human–wildlife conflicts

I just read a good paper on the management of existing and emerging human–wildlife conflicts authored by Piran C. L. White and Alastair I. Ward.

Human wildlife conflict is a product of a combination of human population growth, increased pressure on land and natural resources and climate change. Differences crop up when the factor is resource that can be exploited for economic or cultural benefit, or where the conservation of wildlife is at odds with human population growth or development pressure.

The authors say conflicts can be exacerbated by an incomplete understanding of their causes and/or inappropriate intervention measures. In this paper the authors highlight the potential strategic benefits that can be made by an interdisciplinary approach to human–wildlife conflict situation, by integrating knowledge and understanding across the natural and social sciences. They also stress the potential tactical benefits from combining new approaches to management with more traditional ones.

The researchers say monitoring should play a more prominent role, both in assessing the role of stakeholder engagement in participatory decision-making and in contributing to the evidence base that will allow competing hypotheses about specific systems to be evaluated in an iterative manner. The researchers signs off saying that such holistic approach will help to develop more effective, but also more ethically and environmentally responsible, human–wildlife conflict management for the future.

I am indebted to Dr Piran C. L. White for graciously sending me a copy of the paper.

Interdisciplinary approaches for the management of existing and emerging human–wildlife conflicts

Piran C. L. White and Alastair I. Ward

Wildlife Research, 2010, 37, 623–629

RESPONSE of Dr ULLAS KARANTH TO THE NATIONAL TIGER ESTIMATION REPORT

The latest Tiger estimation report released on 28-3-2011 reports an increase in adult tiger numbers to 1636 (1706 including Sunderbans). The previous estimate of 2007 was 1411 tigers. This is an increase of 16% compounded over 4 years. This tantamount to the view that the previous decline of tigers has been reversed. The threats faced by tigers have not diminished in last four years. It has gone up is some areas. So it is a wee bit difficult to digest the claimed reversal of the decline of tigers. There is an urgent need to evaluate full details of how these tiger numbers have been arrived at.

I found the response by Dr Ullas Karanth to the National Tiger Estimation Report very germane. It hits the nail on the head.

Dr Ullas Karanth says “Most of India’s reproducing tiger populations are now concentrated in 10% of all tiger habitat that holds 90% of all our tigers.  These 40 or so ‘source populations’ are under grave threat and need to be ecologically monitored annually using intensive camera trapping (as prescribed in the proposed Phase 4of the national estimation, which is yet to even begin). Monitoring of tracks by Forest Guards is not a substitute for such reliable monitoring using camera traps or DNA sampling as has already been proven earlier in places where tigers vanished even as guards did similar patrol-based monitoring. To me the most serious flaw in the present government effort is the basic futility of trying to generate all-India level tiger counts once in 4 years, even while ignoring critical task of intensively monitoring key source populations year after year”

Dr Ullas Karanth goes on to add “The time has now come to switch from these once in five year national estimation (termed Phases 1 to 3) and focus intensive camera trap or DNA monitoring of tiger source populations so that we can track the fate of individual tigers, and estimate survival and recruitment rates to gauge how each of these populations is faring. If we do not shift to such focused, intensive monitoring approaches, we are at serious risk of losing more and more key populations even while we celebrate supposed ‘increases’ from these national counts (it is well known that half the tiger reserves lost most of their tigers in the past decadesdespite these national counts!)”

“On a more technical note, the full process of how these tiger numbers are generated for individual tiger populations and landscapes, has not been made public in a scientifically acceptable manner. Only one scientific paper, which explains only a part of this protocol, has been published in 2011, based on data from the last round of estimation in 2007. While this is not the place for a technical discussion, I see serious deficiencies in the methodology which has been published.”

Here is my view on this .Remember the Amur tiger report published in Mammalian Biology recently? The researchers said the Amur tigers have been reduced to an effective population of fewer than 14 animals even though approximately 500 Amur tigers live in the wild. Genetic bottleneck during the tigers' recent history has been brought out by the research. Mode shift in allele frequencies tests were positive, while the M-ratio test was negative, indicating the likelihood of a contemporary rather than a historical population bottleneck.  Against the backdrop of this the suggestions by Dr Ullas Karanth assumes great significance.

I fully endorse the view of Dr Ullas Karanth that to achieve real progress in Tiger monitoring, government must give up its present monopoly over tiger monitoring and bring in outside expertise and resources in order to ensure greater reliability, transparency and credibility in monitoring the fate of our national animal.  

My internet connection is down again

My internet connection has gone bust again. I am posting this from my friend's computer. I am going to be erratic till the guys fix the problem. As usual the provider say there is a cable fault.

Good Taxonomists – An endangered lot

There is undoubtedly a decline in good taxonomists worldwide. Juxtapose this against the fact that there is an estimated 5.4 million yet-to-be-discovered animal species. Researchers have identified 1.4 million animal species so far. At the current pace of 16,000 new animal species cataloged annually, it will take 360 years to complete the job. On an average, each taxonomist describes about 25 new species during his or her career. Recently tiger beetle specialist David Pearson of Arizona State University in Tempe said "There are not going to be more taxonomists in the future. It's just a pipe dream as far as I'm concerned,"

The recent comments of Dr David Pearson of Arizona State University are very pertinent here. He calls for inclusion of more amateurs and laypeople, who are already making substantial taxonomic contributions but whose work is often marginalized by turf-jealous academics. He says if you have a pair of binoculars or a microscope, there are at least 5 million species out there awaiting your gaze.

It is against this backdrop that I found a recent paper titled “Recovery Plan for the Endangered Taxonomy Profession” authored by David L. Pearson, Andrew L. Hamilton, and Terry L. Erwin published in BioScience very interesting. They propose changes in priorities for training taxonomists to reverse the trend. Here is the gist of what they say “Academically trained professionals, parataxonomists (local assistants trained by professional biologists), youths educated with an emphasis on natural history, and self-supported expert amateurs are the major sources of taxonomists. Recruiting effort from each category is best determined by public attitudes toward education, as well as the availability of discretionary funds and leisure time. Instead of concentrating on descriptions of species and narrow studies of morphology and DNA, the duties of the few professional taxonomists of the future also will be to use cyberspace and a wide range of skills to recruit, train, and provide direction for expert amateurs, young students, parataxonomists, the general public, and governments”.

Recovery Plan for the Endangered Taxonomy Profession

BioScience 61(1):58-63. 2011
doi: 10.1525/bio.2011.61.1.11

The reversal of genetic decline

We constantly talk about isolated populations and genetic erosion.  Very little is known about the time-scale over which adverse genetic effects develop in natural populations. The other day I was discussing the subject with my friend Ramesh. Ramesh wanted to know whether genetic rescue of isolated populations is possible or not.

Yes, it is possible. We have a good example from National Bison Range of northwest Montana where Bighorn sheep from Alberta's Banff National Park started a new herd with the release of 12 animals. The herd grew rapidly, but soon peaked at 90 animals and ultimately stabilized at around 40. Genetic diversity of the insular group was very low, restricted to the limited gene pool of the dozen founding animals. For 11 generations the bottleneck continued, overwhelmed by deleterious genes.  Then wild sheep, totalling 15 animals, captured mainly from other Montana herds, were transplanted to National Bison Range over a period from 1985 to 1994. The migrants brought about dramatic changes to the herd's reproductive fitness. The herd's population growth rate reversed and was on the upswing again. The newly-contributed genes overshadowed the negative effects.

Yes, genetic principles deserve wider recognition as practical management tools.

Have a wonderful weekend. The next update will be on Tuesday

Sharks and “mental maps”

Now, this is amazing. Sharks making “mental maps” that allow them to pin-point destinations up to 50km away. I read this in a new paper by Yannis P. Papastamatiou ,Daniel P. Cartamil, Christopher G. Lowe, Carl G. Meyer, Brad M. Wetherbee and Kim N. Holland titled “Scales of orientation, directed walks and movement path structure in sharks” published in Journal of Animal Ecology

The researchers analysed tracking  data from three shark species tagged with acoustic transmitters, and found that they took directed paths from place to place. This shows a capacity to store maps of key sites. The researchers used statistical techniques to show that the journeys were not made by accident.

Blacktip reef sharks (Carcharhinus melanopterus), although widespread around the Pacific, appear to have small ranges within their home reef system.

On the other hand, tiger sharks (Galeocerdo cuvier) can cover huge distances. Tags have been recovered from individuals more than 3,000km away from where they were attached

The researchers say animal search patterns reflect sensory perception ranges combined with memory and knowledge of the surrounding environment. Random walks are used when the locations of resources are unknown, whereas directed walks should be optimal when the location of favourable habitats is known. However, directed walks have been quantified for very few species. 

Tiger sharks performed directed walks at large spatial scales (at least 6–8 km). Thresher sharks also showed directed movement (at scales of 400–1900 m), and adult threshers were able to orient at greater scales than juveniles, which the researchers say suggest that learning improves the ability to perform directed walks. . Blacktip reef sharks had small home ranges, high site fidelity and showed no evidence of oriented movements at large scales. 

The researchers conclude that Sharks can perform directed walks over large spatial scales, with scales of movements reflecting site fidelity and home range size. The researchers signs off saying “Understanding when and where directed walks occur is crucial for developing more accurate population-level dispersal models.” 

Scales of orientation, directed walks and movement path structure in sharks

Yannis P. Papastamatiou ,Daniel P. Cartamil, Christopher G. Lowe, Carl G. Meyer, Brad M. Wetherbee and Kim N. Holland

Article first published online: 1 MAR 2011

DOI: 10.1111/j.1365-2656.2011.01815.x

Journal of Animal Ecology

Landscape level monitoring of species abundance and distribution

Managing at landscape levels is acquiring increasing importance. Metapopulation management, maintaining transfrontier protected areas and softening the agricultural matrix is considered priority items. It is against this backdrop that I found a recent paper by Julia P. G. Jones titled “Monitoring species abundance and distribution at the landscape scale” very useful. In this paper the authors address some of the challenges presented by monitoring at the landscape scale, how models of species distribution can be used to inform policy, and discuss how monitoring at the global-scale could be approached. 

Collecting data over large areas is time consuming and costly. The authors present ideas for low-cost approaches against what they call “more data-hungry methods “ (indices of abundance vs. direct density estimates, and species distribution models built from presence-only vs. presence/absence data). 

Occupancy modelling is a useful approach for landscape-scale monitoring. It is a relatively low-cost operation .The authors discuss challenges, such as non-random sampling locations and periodical unavailability for detection, in using detection/non-detection data for monitoring species distribution. The researchers say such data can also provide estimates of abundance and show how existing models can be modified to allow the abundance of multiple species to be estimated simultaneously.

The researchers contend that models of species distribution can be used to project likely future scenarios and thus inform conservation planning where distributions are likely to change because of climate change or changing disturbance patterns.

Monitoring is needed for many purposes including auditing past management decisions and getting to know about future options. The authors’ sign off saying “recent global targets for conservation require monitoring which can report trends at the global-scale. Integrating data collected at a variety of scales to draw robust inference at the scale required is a challenge which deserves more attention from applied ecologists”.

Monitoring species abundance and distribution at the landscape scale

Julia P. G. Jones

Journal of Applied Ecology

Article first published online: 7 JAN 2011    DOI: 10.1111/j.1365-2664.2010.01917.x

Reducing Wildlife–Vehicle Collisions

Last weekend we were driving through Wynad sanctuary. Naturally we discussed the crossing of wild animals.  We had only recently read a good paper from US which appeared in Journal of Wildlife Management

Wildlife managers and transportation mangers are a worried lot when it to comes to roads passing through wildlife habitats. Mitigating the impacts of highways on wildlife and increasing driver safety is high on their agenda.

Wildlife underpasses are a good option but this has to be constructed very carefully. In this piece of research the researchers used camera and track surveys to evaluate wildlife use before and after construction of 3 wildlife underpasses and associated fencing on a new section of United States Highway 64 in Washington County, North Carolina, USA. Theyrecorded 242 occasions of white-tailed deer (Odocoileus virginianus) use of underpass areas before highway construction began.

After the construction of the underpass they collected 2,433 photographs of 9 species with deer representing 93% of all crossings. White-tailed deer use of underpass areas averaged 6.7 times greater after the new highway and underpasses were completed.

The researchers recorded 3,614 wildlife crossings of ≥20 species based on track counts. This represented most medium and large mammals known to occur in the area and several reptiles and birds. After completion of the highway wildlife mortality due to vehicle collisions were recorded during a 13-month period. There were 128 incidences representing ≥24 species. Within fenced highway segments, mortalities were lowest near underpasses and increased with distance from the underpasses.

More mortality was recorded in fenced areas when compared to unfenced areas. The researchers say with greater distance from an underpass, animals with smaller home ranges seemed less likely to reach the underpass and instead attempted to climb over or crawl under fencing.

The research clearly demonstrated that underpasses and fencing reduced the number of deer–vehicle collisions. The researchers sign off saying “Continuous fencing between underpasses may further reduce the number of vehicle collisions for deer but additional design features (e.g., buried fencing) should be considered for other wildlife species.”

Effectiveness of Wildlife Underpasses and Fencing to Reduce Wildlife–Vehicle Collisions

Matthew F. McCollister and Frank T. van Manen

Journal of Wildlife Management 74(8):1722-1731. 2010 

Amur tigers teetering on the brink?

The latest reports about Amur tigers (Panthera tigris altaica), from a team of scientists from Russia, Spain and Germany, appearing in the latest issue of journal Mammalian Biology is really worrying.

The researchers say the Amur tigers have been reduced to an effective population of fewer than 14 animals. Approximately 500 Amur tigers live in the wild, but the effective population is a measure of the genetic diversity of the Amur tiger.

Genetic bottleneck during the tigers' recent history has been brought out by the research.  Mode shift in allele frequencies tests were positive, while the M-ratio test was negative, indicating the likelihood of a contemporary rather than a historical population bottleneck.   This translates in to a situation where any vulnerability to disease or rare genetic disorders is likely to be passed on to the next generation. A more genetically diverse population of animals has a much better chance of survival. The research highlights the fact that detection of genetic bottleneck signatures in wildlife species is highly relevant for conservation. 

Siberian tiger's recent population bottleneck in the Russian Far East revealed by microsatellite markers

Samer Alasaad, Ramón C. Sorigue^, Galina Chelomin^,Yury Petrovich Sushitsk and Joerns Fickel

Mammalian Biolog