Patrick's Wren Marsh

Deval Dholakia

108252916

Preservation of Patrick’s marsh wren Cisothorus palustris dawsonii commonl! known as Patrick’s marsh wren is a species of  "ird local to southeastern Central #all #alle! e! in California$ %t is considered an isolated population of the species Cisothorus palustris also known as &arsh wren$ 'his particular t!pe of "ird is an inha"itant of (rasslands and wetlands such as marshes and creeks$ Patrick’s marsh wren are limited in the distance the! travel for new "reedin( " reedin( (rounds and are usuall! restricted to appro)imatel! 100 km awa! from their place of ori(in$ 'he marsh wren mi(rate durin( the winter to *a+a California "ut return to Central #alle! #alle! in order to "reed and raise their offsprin( in the sprin($ ,reen #alle! -anch a lar(e "eef producer has the intent of removin( one of the natural ha"itats of the marsh wren Phillip .lat in order to inte(rate a dike alon( the river which will allow the surroundin( ranches to "e unharmed un harmed "! seasonal floodin($ 'he dike if "uilt will directl! interfere with one of the four marsh wren ha" itats and therefore will affect the species livin( in the area for the worse$ /s an environmentalist it is in m! "est interest to (uarantee safet! for this species and "! allowin( the ,reen #alle! #alle! -anch to take control of the area that includes one of the few remainin( ha"itats ha" itats of Patrick’s marsh wren % wouldn’t "e fulfillin( m! dut!$ %n this paper % will e)plain wh! % am a(ainst the "uildin( of the dike which runs throu(h the Phillip .lat$ 'here is no reason for a species wh ich alread! has onl! a few natural ha"itats to lose one ha"itat that has a lar(e influence on survival rates of the "irds$ %n order to ar(ue for this  position % will provide evidence to support the claim that "uildin( a dike will do more harm than (ood for Patrick’s wren marsh$

%n order to e)plicate m! ar(ument further a series of simulations usin( -/&/ were conducted in which various scenarios were depicted in order to understand effects of "uildin( a dike that runs throu(h Phillip .lat$ 'here were a total of five potential models that displa! the effects on Patrick’s marsh wren$ 'he first simulation is known as naltered '!pe which is the constantcontrol in the model where the Phillip .lat ha" itat is unchan(ed and the total initial a"undance is 300 individuals$ 'he second simulation is known as the naltered de(raded ha"itat in which Phillip .lat is slowl! de(radin($ 'he carr!in( capacit! o f Philip .lat in this model is decreasin( "! 1$ 'he initial a"undance remains 300$ 'he third simulation is also known as naltered de(radin( ha"itat and is similar to the second one4 however the carr!in( capacit! is decreasin( "! 2$ ver!thin( else is unchan(ed in respect to simulation one$ %n simulation four also known as /ltered ha"itat with no remediation % see a model where Phillip .lat is completel! destro!ed and "ecause of this the collective initial a"undance amon(st the four ha"itats is no lon(er 300 rather 05$ 'he last simulation is used to represent the introduction of a dike$ %n this scenario half of the Phillip .lat population is translocated to another &arsh wens ha"itat Delin(er &eadow and then Phillip .lat is destro!ed in order to accommodate the dike$ 'he total population si7e is 52 individuals$ %n 'a"le 1 % see a clear distinction in pro"a"ilities of the species fallin( "elow 200 individuals within the five models$ %n the first simulation there is a pro"a"ilit! of appro)imatel! 83$ 'his su((ests that there is an 83 chance that the population falls "elow 200 individuals$ *ecause this is the control simulation % used this one to compare and contrast the other simulations in order to "etter understand the d!namics of the ha"itat$ imulation two has a lower   pro"a"ilit! 8$ 'his means that the unaltered de(radin( ha"itat where the carr!in( capacit! is decreasin( "! one individual ever! !ear has a rate of fallin( "elow 200 individuals less than the control$ imilarl! the third simulation has a risk of 81 which is less than "oth previous

simulations$ 'he rate of fallin( "elow 200 individuals is the hi(hest in the fourth simulation where there is an altered ha"itat "ut no remediation to compensate$ 'he risk is appro)imatel! 9 and this clearl! displa!s that eliminatin( Phillip .lat completel! is ha7ardous to the survival of the species$ :ast "ut not least in simulation five there is an 8; risk of fallin( "elow 200 individuals which displa!s that there is a ne(ative cause and effect relationship "etween destro!in( the Philip .lat ha"itat and shiftin( the "irds and the surviva"ilit! of the "irds$ %n ta"le 2 we see the population si7es where the risk of e)tinction is 100$ 'he hi(hest  population si7e occurs in the second simulation 526 individuals$ imilarl! the third simulation holds the second hi(hest population si7e of 3;9 individuals$ 'he lowest is seen "! the complete demolition of Phillip .lat or simulation  at 9 individuals$ .or the control simulation we have a population si7e of 352$ :astl! for the fifth simulation the population si7e is 6 individuals$ %n order to further understand the various factors affectin( the population a sensitivit! anal!sis was conducted$
continue with their efforts to create a dike that runs throu(h Phillip .lat "ecause as we can see in our sensitivit! anal!sis Phillip .lat is an inte(ral part of Patrick’s marsh wren as well as maintainin( the rest of the ha"itats$ %n ta"le  as previousl! noted the two simulations have a lar(e difference in risk of e)tinction$ Due to the nature of the marsh wren dispersal mainl! occurs near "reedin( (rounds and therefore most "irds travel within a smaller ran(e of kilometers$ ven if we were to increase the initial a"undance of 'hree=&iles &arsh the rate of e)tinction would still "e si(nificantl! lar(e if Phillip .lat were destro!ed "ecause it is the cen ter of the other ha"itats therefore creatin( a lar(er distance "etween the other ha"itats in its a"sence$ 'he rate of survival would in turn decrease si(nificantl! "ecause resource availa"ilit! and  "reedin( would "e affected$ /s discussed in this paper it is imperative that Phillip .lat "e maintained in order to sustain the marsh wren population$ *! allowin( a dike to "e inte(rated within the river ,reen #alle! -anch is catal!7in( the deterioration of the species$ %n order to further sta"ili7e the marsh wren population the old dike that is located near the Delin(er &eadow should "e removed to allow the species to prevail and prosper$ %n order to further the research that occurs re(ardin( Patrick marsh wren preservation it is necessar! to run multiple sensitivit! anal!sis e)periments to understand the direct and indirect causes of population decline andor population increase$ 'his will aid our efforts to preserve the species$

imulation 1

$83

imulation 2

$8

imulation 

$81

imulation 3

$9

imulation 5

$8;

/ppendi)

imulation 1

362

imulation 2

526

imulation 

3;9

imulation 3

9

imulation 5

6

'a"le 1 -ates of fallin( "elow 200

individuals for each simulation$

'a"le 2 Population si7e when the risk of e)tinction is 100

imulation /

$80

imulation *

$91

'a"le  ensitivit! /nal!sis imulations$ -isk of fallin( "elow 200 individuals$